Recycling device and method for waste materials in lithium pre-embedding process of lithium ion capacitor

Abstract

The invention provides a lithium ion capacitor lithium pre-embedding process waste recovery device and method, and the device comprises an oxidation unit, an activated carbon adsorption unit and a drying regeneration unit which are connected in sequence, the oxidation unit is provided with a carrier gas inlet, a carrier gas outlet, a production waste inlet and outlet door and a laminate for placing production waste, an air passage is arranged on the shelf board; an activated carbon adsorption unit, wherein an adsorption filter element is arranged in the activated carbon adsorption unit; and the drying regeneration unit is filled with a drying agent. By adopting the technical scheme disclosed by the invention, the waste material in the lithium pre-embedding process of the lithium ion capacitor is recycled, so that the potential safety hazard in the production process of the lithium ion capacitor can be avoided, and the recycling efficiency of the lithium element reaches 80% or above; after the waste lithium ion capacitor and the lithium ion battery are treated, the lithium element contained in the negative electrode material can be recycled, and the treatment process is safe, environment-friendly and environment-friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical energy storage and resource recovery, and in particular relates to a device and method for recovering waste materials in a lithium ion capacitor pre-embedded lithium process. Background Art

[0002] Lithium-ion capacitors are a new type of electrochemical energy storage device with advantages such as high energy density, high power density and long cycle life, and have a wide range of energy storage application scenarios. Usually, the positive electrode material of lithium-ion capacitors is a capacitive material, such as activated carbon and graphene, etc.; the negative electrode material is a battery material that can reversibly insert / extract lithium ions, such as graphite, soft carbon, hard carbon and silicon materials.

[0003] The pre-lithium embedding process is one of the effective means to improve the electrochemical performance of lithium-ion capacitors. In the preparation process of lithium-ion capacitors, the significance of pre-lithium embedding is that the amorphous carbon, graphene, silicon-based and other negative electrode materials used in the negative electrode of lithium-ion capacitors have low coulombic efficiency in the first week (80~90%), resulting in a large consumption of lithium ions in the formation process of lithium-ion capacitors; and the capacity in the potential range of 1.0~3.0 V accounts for a large proportion, and this part of the capacity cannot be effectively used by lithium-ion capacitors in the working voltage range. Pre-lithium embedding can compensate for the consumption of lithium ions and reduce the potential of the negative electrode to the working range, thereby increasing the device platform voltage of lithium-ion capacitors and improving the power density and energy density of lithium-ion capacitors.

[0004] The method of pre-embedding lithium may include embedding lithium from the positive electrode and embedding lithium from the negative electrode, wherein embedding lithium from the positive electrode refers to doping lithium-rich compounds into the positive electrode material, and lithium ions are irreversibly extracted and embedded into the negative electrode material during the charging process. Such compounds include lithium nitride Li3N, Li2MoO3, Li5ReO6, Li6CoO4, Li2CuO2, Li5FeO4, Li2C4O4, etc., but there will be problems such as gas production during the production process. Embedding lithium from the negative electrode includes pressing / bonding passivated lithium powder (SLMP) or metal lithium foil to the surface of the negative electrode, and pre-embedding lithium during the charge and discharge process by electrochemical or short-circuit methods. However, if the method of embedding lithium at the negative electrode is adopted, due to the extremely high reactivity of lithium powder or metal lithium foil, it is easy to react with oxygen and nitrogen in the air, and it will react violently with water vapor or even burn, which is easy to cause safety accidents in the production process of lithium ion capacitors. Therefore, the pre-embedding process waste generated in the production process of lithium ion capacitors needs to be properly handled and recycled. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a device and method for recycling waste materials in the pre-lithium embedding process of lithium ion capacitors, which can safely handle the pre-lithium embedding waste materials generated in the production process of lithium ion capacitors and recycle lithium elements. It can also be used to recycle lithium elements in discarded lithium ion capacitor monomers and lithium ion battery cells.

[0006] The specific technical solutions are as follows:

[0007] A device for recycling waste materials in a lithium ion capacitor pre-lithium embedding process, comprising:

[0008] The oxidation unit is provided with a carrier gas inlet 101 at the bottom of the oxidation unit, a carrier gas outlet 104 at the top of the oxidation unit, a production waste inlet and outlet door 105 at the side of the oxidation unit, 1 to 1000 layers 102 for placing production waste are provided inside the oxidation unit, and 1 to 10000 air channels 103 are provided on the layers, and the area of ​​a single air channel is 1 to 100 mm 2 ;

[0009] Preferably, the number of layers 102 arranged in the recycling device for waste materials from the pre-lithium embedding process of small-sized lithium-ion capacitors is 10, and the number of air passages 103 arranged is 300; the number of layers 102 arranged in the recycling device for waste materials from the pre-lithium embedding process of large-sized lithium-ion capacitors is 100, and the number of air passages 103 arranged is 1000; this ensures that during the recycling process of waste materials from the pre-lithium embedding process of lithium-ion capacitors, the air pressure loss and the power loss are minimized, and the recycling efficiency of waste materials from the pre-lithium embedding process of lithium-ion capacitors is the highest.

[0010] An activated carbon adsorption unit is provided with an adsorption filter element, and the adsorption filter element is made of a material including activated carbon; for example, the adsorption filter element is made by mixing activated carbon and a binder and then heating and molding them.

[0011] The drying and regeneration unit is provided with a desiccant, and the types of the desiccant are: silica gel, anhydrous calcium chloride, anhydrous copper sulfate, anhydrous sodium sulfate, anhydrous magnesium sulfate, soda lime, quicklime.

[0012] A method for recycling waste materials from the pre-lithium embedding process of lithium ion capacitors:

[0013] The carrier gas enters from the bottom carrier gas inlet 101 of the oxidation unit, passes through the air channel 103 in the oxidation unit, and flows out from the carrier gas outlet 104, passes through 1 to 10 activated carbon adsorption units to remove organic solvents and moisture in the carrier gas, and then flows through the drying and regeneration unit to further remove moisture in the carrier gas, and then enters the oxidation unit for recycling, and supplements with an appropriate amount of dry carrier gas to ensure the stability of the carrier gas flow rate; preferably, the number of activated carbon adsorption units is 3, which can achieve a balance between adsorption efficiency and cost;

[0014] After the waste from the pre-lithium embedding process enters the oxidation unit, it reacts with the oxygen in the carrier gas and is oxidized into stable lithium oxide or lithium carbonate. After being classified and crushed, it is immersed in water, and lithium hydroxide and lithium carbonate are crystallized in the leachate to achieve lithium recovery.

[0015] The carrier gas is a mixed gas of oxygen and carbon dioxide, and the volume content percentage of oxygen is 10% to 100%, preferably 10% to 40%.

[0016] The operating temperature of the oxidation unit is 25-100°C, preferably 40-60°C. In this temperature range, the rapid oxidation of the elemental lithium can be achieved without the explosion of the organic solvent. The compatible elemental lithium can exist in the form of a large-area metal lithium foil, or in the form of lithium residues adhering to the current collector and the isolation polymer film, or in the negative electrode sheet after pre-embedded lithium.

[0017] Beneficial effects:

[0018] By adopting the technical solution disclosed in the present invention, the recycling and treatment of waste materials in the pre-lithium embedding process of lithium ion capacitors can eliminate the potential safety hazards in the production process of lithium ion capacitors, and the recovery efficiency of lithium elements can reach more than 80%. By adopting the technical solution disclosed in the present invention, after the discarded lithium ion capacitors and lithium ion batteries are processed, the lithium elements contained in the negative electrode materials can be recovered, and the processing process is safe and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of a device for recycling waste materials from the pre-lithium embedding process of lithium-ion capacitors;

[0020] Figure 2 A schematic diagram of a recycling process for waste materials from a lithium ion capacitor pre-lithium embedding process;

[0021] In the figure, 101 is a carrier gas inlet, 102 is a layer plate, 103 is an air channel, 104 is a carrier gas outlet, and 105 is a production waste inlet and outlet door. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. In order to achieve the above-mentioned purpose, the present invention adopts the following technical solution:

[0023] Example 1

[0024] like Figure 1 As shown, a device for recycling waste materials in the process of pre-lithium embedding of lithium ion capacitors comprises: an oxidation unit, an activated carbon adsorption unit and a drying and regeneration unit. The oxidation unit, the activated carbon adsorption unit and the drying and regeneration unit are connected in sequence.

[0025] The oxidation unit has a carrier gas inlet 101 at the bottom, a carrier gas outlet 104 at the top, a production waste inlet and outlet door 105 at the side of the oxidation unit, 10 layers 102 for placing production waste are arranged inside the oxidation unit, and 300 air channels 103 are arranged on the layers, and the area of ​​a single air channel is 10mm 2 ;

[0026] An activated carbon adsorption unit is provided with an adsorption filter element, which is formed by mixing activated carbon and a binder and heating at 150°C to adsorb organic solvents and a small amount of water in the carrier gas;

[0027] The drying and regeneration unit is provided with a silica gel desiccant for removing moisture from the carrier gas.

[0028] like Figure 2 As shown, a method for recycling waste materials from the pre-lithium embedding process of lithium ion capacitors:

[0029] The carrier gas enters from the carrier gas inlet 101 at the bottom of the oxidation unit, passes through the air channel 103 in the oxidation unit, and flows out from the carrier gas outlet 104. It passes through three activated carbon adsorption units to remove organic solvents and moisture in the carrier gas, and then flows through the drying and regeneration unit to further remove moisture in the carrier gas. It is then passed into the oxidation unit for recycling, and an appropriate amount of dry carrier gas is added to ensure the stability of the carrier gas flow rate.

[0030] After the waste from the pre-lithium embedding process enters the oxidation unit, it reacts with the oxygen in the carrier gas and is oxidized into stable lithium oxide or lithium carbonate. After being classified and crushed, it is immersed in water, and lithium hydroxide and lithium carbonate are crystallized in the leachate to achieve lithium recovery.

[0031] The carrier gas is a mixed gas of oxygen and carbon dioxide, and the volume content of oxygen is 40%.

[0032] The operating temperature of the oxidation unit is 60°C. In this temperature range, the rapid oxidation of the elemental lithium can be achieved without the explosion of the organic solvent. The compatible elemental lithium can exist in the form of a large-area metal lithium foil, or in the form of lithium residues adhering to the current collector and the isolating polymer film, or in the negative electrode sheet after pre-embedded lithium.

[0033] Example 2

[0034] Rolled lithium metal foil is usually separated by polyethylene terephthalate (PET) separator to avoid adhesion between lithium metal foils. After the lithium metal foil is used, a small amount of lithium metal will remain on the PET separator, which will cause safety hazards if it is directly mixed into domestic waste. The PET separator waste is placed in the recovery device described in Example 1 for treatment, and the lithium element in the waste is crystallized and precipitated. The treated PET separator waste is subjected to conventional solid waste recovery, and the recovery rate of lithium element reaches more than 95%.

[0035] Example 3

[0036] The industrial waste generated during the production of lithium-ion capacitor cells may contain lithium metal debris and powder, and some semi-finished products contain metal lithium foil or lithium ribbon. These lithium-containing substances will burn when they encounter combustibles in humid air, so they need to be handled safely. These production wastes are placed in the recovery device described in Example 1 for treatment, and the lithium element in the waste is crystallized and precipitated. The treated production wastes are subjected to garbage classification and conventional solid waste recycling.

[0037] Example 4

[0038] The discarded lithium ion capacitors or lithium ion batteries are put to a 0% state of charge (SOC0%) for disassembly, and the waste is sent to the recovery device described in Example 5. The organic volatile solvent in the lithium ion capacitors and lithium ion batteries is adsorbed by the activated carbon adsorption unit, and the single lithium element inserted into the negative electrode is oxidized into lithium oxide or lithium carbonate, which is dissolved and crystallized. The treated production waste is subjected to garbage classification and conventional solid waste recycling, and the recovery rate of lithium elements is more than 85%.

[0039] Example 5

[0040] like Figure 1 As shown, a device for recycling waste materials in the process of pre-lithium embedding of lithium ion capacitors comprises:

[0041] 1 oxidation unit, a carrier gas inlet 101 is arranged at the bottom of the oxidation unit, a carrier gas outlet 104 is arranged at the top of the oxidation unit, a production waste inlet and outlet door 105 is arranged on the side of the oxidation unit, 100 layers 102 for placing production waste are arranged inside the oxidation unit, 1000 air channels 103 are arranged on the layers, and the area of ​​a single air channel is 1mm 2 ;

[0042] 5 activated carbon adsorption units, each of which is equipped with an adsorption filter element, which is made by mixing activated carbon and a binder and then heating and molding at 120°C in a vacuum, and is used to adsorb organic solvents and a small amount of water in the carrier gas;

[0043] 1 drying and regeneration unit, which is equipped with anhydrous calcium chloride desiccant for removing moisture from the carrier gas. The anhydrous calcium chloride desiccant can be recycled after removing moisture by heating.

[0044] A method for recycling waste materials from the pre-lithium embedding process of lithium ion capacitors:

[0045] The carrier gas enters from the carrier gas inlet 101 at the bottom of the oxidation unit, passes through the air channel 103 in the oxidation unit, and flows out from the carrier gas outlet 104. It passes through five activated carbon adsorption units to remove organic solvents and moisture in the carrier gas, and then flows through the drying and regeneration unit to further remove moisture in the carrier gas. It is then passed into the oxidation unit for recycling, and an appropriate amount of dry carrier gas is added to ensure the stability of the carrier gas flow rate.

[0046] After the waste from the pre-lithium embedding process enters the oxidation unit, it reacts with the oxygen in the carrier gas and is oxidized into stable lithium oxide or lithium carbonate. After being classified and crushed, it is immersed in water, and lithium hydroxide and lithium carbonate are crystallized in the leachate to achieve lithium recovery.

[0047] The carrier gas is a mixed gas of oxygen and carbon dioxide, with the volume content of oxygen being 10%. The operating temperature of the oxidation unit is 40°C.

Claims

1. A device for recycling waste materials from the pre-lithium embedding process of lithium ion capacitors, characterized in that: include: oxidation unit, activated carbon adsorption unit and drying regeneration unit; the oxidation unit, activated carbon adsorption unit and drying regeneration unit are connected in sequence; wherein, An oxidation unit, wherein a carrier gas inlet (101) is arranged at the bottom of the oxidation unit, a carrier gas outlet (104) is arranged at the top of the oxidation unit, a production waste inlet and outlet door (105) is arranged on the side of the oxidation unit, 1 to 1000 layers (102) for placing production waste are arranged inside the oxidation unit, and 1 to 10000 air channels (103) are arranged on the layers, and the area of ​​a single air channel is 1 to 100 mm 2 ; An activated carbon adsorption unit, wherein an adsorption filter element is provided in the activated carbon adsorption unit, and the adsorption filter element is made of a material including activated carbon; A drying and regeneration unit is provided with a desiccant.

2. The device according to claim 1, characterized in that The desiccant is silica gel, anhydrous calcium chloride, anhydrous copper sulfate, anhydrous sodium sulfate, anhydrous magnesium sulfate, soda lime or quicklime.

3. The device according to claim 1, characterized in that The number of the layer plates (102) is 10 or 100.

4. The device according to claim 1, characterized in that The number of airways (103) is 300 or 1000.

5. The device according to claim 1, characterized in that The area of ​​a single airway is 1~90mm 2 .

6. A method for recycling waste materials from the pre-lithium embedding process of lithium ion capacitors, characterized in that: Using the device as described in any one of claims 1 to 5, the method comprises the following steps The carrier gas enters from the bottom carrier gas inlet (101) of the oxidation unit, passes through the air passage (103) in the oxidation unit, flows out from the carrier gas outlet (104), passes through 1 to 10 activated carbon adsorption units to remove organic solvents and moisture in the carrier gas, then passes through the drying and regeneration unit to further remove moisture in the carrier gas, and then enters the oxidation unit for recycling, and an appropriate amount of dry carrier gas is added to ensure a stable carrier gas flow rate; After the waste from the pre-lithium embedding process enters the oxidation unit, it reacts with the oxygen in the carrier gas and is oxidized into stable lithium oxide or lithium carbonate. After being classified and crushed, it is immersed in water, and lithium hydroxide and lithium carbonate are crystallized in the leaching solution to achieve lithium recovery. The carrier gas is a mixture of oxygen and carbon dioxide, with the volume content of oxygen ranging from 10% to 100%; The operating temperature of the oxidation unit is 25~100℃.

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