Pole piece recovery system and pole piece recovery method

Abstract

The invention relates to the technical field of lithium battery recovery, in particular to a pole piece recovery system and a pole piece recovery method. The pole piece recovery system comprises a crusher, a first crusher, a first screening device, a second crusher, a second screening device and a first hopper which are connected in sequence, a positive electrode discharge port and a negative electrode discharge port are formed in the first hopper, and the positive electrode discharge port is sequentially connected with a first grinder and a rocking sieve; a rocking sieve coarse material discharge port, a rocking sieve intermediate material discharge port and a rocking sieve fine material discharge port are formed in the rocking sieve, the rocking sieve intermediate material discharge port is sequentially connected with a second grinder and a second hopper, the second hopper is connected with the first hopper through a negative pressure pipeline, and a negative pressure fan is arranged on the negative pressure pipeline; the cathode discharge hole is connected with a copper hopper; according to the pole piece recovery method, the positive pole piece or the negative pole piece is recovered by using the pole piece recovery system. According to the invention, the positive plate and the negative plate can be recycled respectively, and the universality is high; the recycling rate of the positive plate can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery recycling, and in particular to a pole piece recycling system and a pole piece recycling method. Background Art

[0002] Waste lithium batteries contain a large number of recyclable components such as various valuable metals and various organic substances. How to recycle lithium batteries safely and efficiently is an important issue in the field of sustainable resource utilization. In the field of lithium battery recycling, the electrode recycling process can recycle the positive and negative electrodes in lithium batteries respectively and has been widely used.

[0003] The main steps of the electrode recycling process are to dismantle the outer shell of the waste lithium battery after discharging it, and then separate the positive electrode and negative electrode in the lithium battery cell for further processing. Among them, the positive electrode is an aluminum foil coated with positive electrode active material, and the negative electrode is a copper foil coated with negative electrode active material. The conventional treatment of positive and negative electrode sheets is mainly to crush and screen the positive and negative electrode sheets respectively, separate the positive electrode sheets into aluminum foil fragments and positive electrode black powder, and separate the negative electrode sheets into copper foil fragments and negative electrode black powder, and then recycle the aluminum foil fragments, copper foil fragments, positive electrode black powder and negative electrode black powder respectively.

[0004] The pole piece recycling process relies on the pole piece recycling system. The existing pole piece recycling system generally includes structures such as crushing devices and screening devices. However, the adhesion strength between the positive electrode active material and the aluminum foil in the waste lithium battery is strong, and the existing pole piece recycling system generally uses the same process to treat the positive and negative pole pieces, which makes it difficult to completely separate the positive electrode active material attached to the surface of the aluminum foil. Therefore, the use of the existing pole piece recycling system and process to recycle the positive and negative pole pieces of lithium batteries has the problem of high impurity content and low purity of the aluminum foil fragments, and low recovery rate of positive black powder. Summary of the invention

[0005] In view of the technical problems that the existing electrode sheet recycling system and electrode sheet recycling process have difficulties in separating the positive electrode active material attached to the surface of the aluminum foil in the positive electrode sheet, the recycled aluminum foil fragments have high impurity content and low purity, and the positive electrode black powder recovery rate is low, the present invention provides a electrode sheet recycling system and an electrode sheet recycling method, which can respectively realize the recycling of positive electrode sheets and negative electrode sheets, and have strong versatility; the large-particle flocs obtained by recycling the positive electrode sheets contain less aluminum, and the small-particle aluminum foil has low impurity content and high purity, which can improve the recovery rate of the positive electrode black powder and further improve the recycling rate of the positive electrode sheets.

[0006] In a first aspect, the present invention provides a pole piece recovery system, comprising a crusher, the crusher is sequentially connected to a first crusher and a first screening device, the first screening device is provided with a first large particle size discharge port and a first powder discharge port, the first large particle size discharge port is sequentially connected to a second crusher and a second screening device, the second screening device is provided with a second large particle size discharge port and a second powder discharge port, and the second large particle size discharge port is connected to the first hopper; The first hopper is provided with a positive electrode discharge port and a negative electrode discharge port, which are connected to the first grinder and the swing screen in sequence; the swing screen is provided with a swing screen coarse material discharge port, a swing screen intermediate material discharge port and a swing screen fine material discharge port, which are connected to the second grinder and the second hopper in sequence; a negative pressure pipe is connected above the second hopper, a negative pressure fan is provided on the negative pressure pipe, and the negative pressure pipe is connected to the first hopper.

[0007] Furthermore, the first screening device is a drum screen or a vibrating screen, and the second screening device is a drum screen or a vibrating screen.

[0008] Furthermore, the crusher and the first pulverizer, the first pulverizer and the first screening device, and the second pulverizer and the second screening device are connected respectively via a feeding device, and the feeding device is selected from a screw feeder, a bucket elevator and / or a belt conveyor.

[0009] Furthermore, the sieve hole diameters of the first screening device and the second screening device are 0.15 mm.

[0010] Furthermore, a large-aperture swing screen and a small-aperture swing screen are arranged in the swing screen. The aperture of the large-aperture swing screen is 5-10 mm, and the aperture of the small-aperture swing screen is 0.15 mm.

[0011] Furthermore, a filter screen is provided at the connection between the second hopper and the negative pressure pipe, and the pore size of the filter screen is 0.15 mm.

[0012] Furthermore, the first powder discharge port, the second powder discharge port, and the swing screen fine material discharge port are respectively connected to the black powder hopper; the swing screen coarse material discharge port is connected to the large particle size material hopper, and the second hopper is connected to the small particle size aluminum hopper.

[0013] In a second aspect, the present invention provides a pole piece recycling method, using the pole piece recycling system to recycle the positive pole piece, the steps comprising: (1) Primary crushing and screening: start the negative pressure fan, then put the positive electrode sheet into the crusher to crush it to obtain positive electrode material, send the positive electrode material to the first crusher for crushing, and send it to the first screening device for screening, discharge the screened positive electrode black powder through the first powder material outlet and collect it, and discharge the remaining positive electrode material through the first large particle size outlet; (2) Secondary crushing and screening: the positive electrode material discharged through the first large particle size outlet is sequentially sent to the second crusher for crushing and sent to the second screening device for screening. The screened positive electrode black powder is discharged and collected through the second powder outlet, and the remaining positive electrode material is discharged through the second large particle size outlet and enters the first hopper; (3) Grinding, grading and screening: open the positive electrode discharge port and close the negative electrode discharge port. The positive electrode material in the first hopper enters the first grinder through the positive electrode discharge port for grinding, and then enters the swing screen for screening into large particles, medium particles and small particles. The large particles are discharged and collected through the coarse material discharge port of the swing screen, and the small particles are discharged and collected through the fine material discharge port of the swing screen. The medium particles enter the second grinder through the intermediate material discharge port of the swing screen for grinding, and then enter the second hopper; Among them, the large particle material is mainly large particle size floccules, the medium particle material is mainly small particle size aluminum foil stained with black powder, and the small particle material is black powder. Through the swing screen screening, the large particle size floccules, the small particle size aluminum foil stained with black powder and the black powder are separated and collected separately, and after the medium particle material is ground by the second grinder, the small particle size aluminum foil is separated from the black powder adhered to its surface, which is convenient for the classification and recycling of different materials; (4) Negative pressure circulation: under the action of the negative pressure fan, the black powder in the second hopper is sucked into the negative pressure pipeline and then sent to the first hopper for circulation treatment; Under the action of the negative pressure fan, the black powder with lighter specific gravity in the second hopper is sucked into the negative pressure pipe, and the small-particle aluminum foil remains in the second hopper for further recycling.

[0014] In a third aspect, the present invention provides a method for recycling anode plates, using the above-mentioned cathode plate recycling system to recycle cathode plates, the steps comprising: (i) primary crushing and screening, the negative electrode sheet is put into a crusher to be crushed to obtain negative electrode material, which is then sequentially sent to the first crusher for crushing and sent to the first screening device for screening, the screened negative electrode black powder is discharged and collected through the first powder material discharge port, and the remaining negative electrode material is discharged through the first large particle size discharge port; (ii) Secondary crushing and screening, the negative electrode material discharged through the first large particle size outlet is sequentially sent to the second crusher for crushing and sent to the second screening device for screening, the screened negative electrode black powder is discharged and collected through the second powder outlet, and the remaining negative electrode material is discharged through the second large particle size outlet and enters the first hopper; After two crushing and screening, the black powder in the negative electrode material is basically discharged through the first powder material outlet and the second powder material outlet, and the negative electrode material entering the first hopper is a high-purity copper foil; (iii) Negative electrode material recovery: opening the negative electrode discharge port, closing the positive electrode discharge port, and discharging and collecting the negative electrode material in the first hopper through the negative electrode discharge port.

[0015] The beneficial effects of the present invention are: 1. The electrode sheet recycling system provided by the present invention can realize the recycling of positive electrode sheets and negative electrode sheets respectively, without using two systems to process positive electrode sheets and negative electrode sheets respectively. It has strong versatility and high recycling efficiency for positive electrode sheets and negative electrode sheets.

[0016] 2. The present invention sets a positive electrode discharge port on the first hopper, which is connected to the first grinder and the swing screen in sequence, and the swing screen intermediate material discharge port of the swing screen is connected to the second grinder and the second hopper in sequence, and the second hopper is connected to the first hopper through a negative pressure pipe, so that when recycling the positive electrode sheets, the positive electrode materials that have undergone two-stage crushing and screening can be further screened into large-particle flocs, black powder and small-particle aluminum foil with black powder, and the small-particle aluminum foil is further separated from the black powder, and the large-particle flocs, small-particle aluminum foil and black powder are collected separately, so as to realize the classified recycling of different materials; the large-particle flocs obtained by recycling the positive electrode sheets contain less aluminum, and the small-particle aluminum foil has low impurity content and high purity, so that the positive electrode black powder is recovered to the greatest extent, and the recycling efficiency of the positive electrode sheets is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a structural schematic diagram of the electrode recovery system in Example 1.

[0019] In the figure, 1-crusher, 2-first crusher, 3-first screening device, 31-first black powder hopper, 4-second crusher, 5-second screening device, 51-second black powder hopper, 6-first hopper, 61-copper hopper, 62-first grinder, 7-swing screen, 71-large particle size material hopper, 72-second grinder, 73-third black powder hopper, 8-second hopper, 81-small particle size aluminum hopper, 82-negative pressure pipe, 83-negative pressure fan. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0021] Example 1 A pole piece recovery system comprises a crusher 1, the crusher 1 is connected to a first crusher 2 via a belt conveyor and a bucket elevator in sequence, the first crusher 2 is connected to a first screening device 3 via a screw feeder, the first screening device 3 is a drum screen, and the screen hole diameter of the first screening device 3 is 0.15 mm; The first screening device 3 is provided with a first large particle size discharge port and a first powder discharge port, the first powder discharge port is connected to the first black powder hopper 31, the first large particle size discharge port is connected to the second crusher 4, the second crusher 4 is connected to the second screening device 5 through a screw feeder, the second screening device 5 is a drum screen, and the sieve aperture of the second screening device 5 is 0.15 mm; The second screening device 5 is provided with a second large particle size discharge port and a second powder material discharge port, the second powder material discharge port is connected to the second black powder hopper 51, and the second large particle size discharge port is connected to the first hopper 6; The first hopper 6 is provided with a positive electrode discharge port and a negative electrode discharge port, the negative electrode discharge port is connected to the copper hopper 61, and the positive electrode discharge port is connected to the first grinder 62 and the swing screen 7 in sequence; A large-aperture swing screen and a small-aperture swing screen are arranged in the swing screen 7. The aperture of the large-aperture swing screen is 5 mm, and the aperture of the small-aperture swing screen is 0.15 mm. A swing screen coarse material discharge port, a swing screen intermediate material discharge port and a swing screen fine material discharge port are arranged on the swing screen 7. The swing screen coarse material discharge port is connected to the large-particle material hopper 71, the swing screen fine material discharge port is connected to the third black powder hopper 73, and the swing screen intermediate material discharge port is connected to the second grinder 72 and the second hopper 8 in sequence. The second hopper 8 is connected to the small-particle aluminum hopper 81, and a negative pressure pipe 82 is connected above the second hopper 8. A filter is provided at the connection between the second hopper 8 and the negative pressure pipe 82, and the pore size of the filter is 0.15 mm; a negative pressure fan 83 is provided on the negative pressure pipe 82, and the negative pressure pipe 82 is connected to the first hopper 6.

[0022] Example 2 A method for recycling anode plates, using the cathode plate recycling system of embodiment 1 to recycle cathode plates, comprising the following steps: (1) Turn on the negative pressure fan 83, then put the positive electrode sheet into the crusher 1 to crush it to obtain the positive electrode material, send the positive electrode material to the first crusher 2 for crushing, and send it to the first screening device 3 for screening, discharge the screened positive electrode black powder through the first powder discharge port and collect it through the first black powder hopper 31, and discharge the remaining positive electrode material through the first large particle size discharge port; (2) The positive electrode material discharged through the first large particle size outlet is sequentially sent to the second pulverizer 4 for pulverization and sent to the second screening device 5 for screening. The screened positive electrode black powder is discharged through the second powder outlet and collected through the second black powder hopper 51. The remaining positive electrode material is discharged through the second large particle size outlet and enters the first hopper 6. (3) The positive electrode discharge port is opened and the negative electrode discharge port is closed. The positive electrode material in the first hopper 6 enters the first grinder 62 through the positive electrode discharge port for grinding, and then enters the swing screen 7 for screening. The large particle material screened out is discharged through the swing screen coarse material discharge port and collected in the large particle size material hopper 71. The small particle material is discharged through the swing screen fine material discharge port and collected in the third black powder hopper 73. The medium particle material enters the second grinder 72 through the swing screen intermediate material discharge port for grinding, and then enters the second hopper 8. (4) Under the action of the negative pressure fan 83, the black powder with a diameter less than 0.15 mm in the second hopper 8 passes through the filter and is sucked into the negative pressure pipe 82, and then sent to the first hopper 6 for circulation treatment; Example 3 A method for recycling anode plates, using the cathode plate recycling system of embodiment 1 to recycle cathode plates, comprising the following steps: (i) The negative electrode sheet is put into a crusher 1 for crushing, and then sent to a first crusher 2 for crushing and sent to a first screening device 3 for screening. The screened negative electrode black powder is discharged through a first powder discharge port and collected through a first black powder hopper 31, and the remaining negative electrode material is discharged through a first large particle size discharge port; (ii) the negative electrode materials discharged through the first large particle size outlet are sequentially sent to the second pulverizer 4 for pulverization and sent to the second screening device 5 for screening. The screened negative electrode black powder is discharged through the second powder outlet and collected through the second black powder hopper 51. The remaining negative electrode materials are discharged through the second large particle size outlet and enter the first hopper 6. (iii) Open the negative electrode discharge port and close the positive electrode discharge port, discharge the negative electrode material in the first hopper 6 through the negative electrode discharge port and collect it in the copper hopper 61 .

[0023] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.

Claims

1. A pole piece recovery system, comprising a crusher, characterized in that: The crusher is connected to the first pulverizer and the first screening device in sequence, the first screening device is provided with a first large particle size discharge port and a first powder discharge port, the first large particle size discharge port is connected to the second pulverizer and the second screening device in sequence, the second screening device is provided with a second large particle size discharge port and a second powder discharge port, and the second large particle size discharge port is connected to the first hopper; The first hopper is provided with a positive electrode discharge port and a negative electrode discharge port, which are connected to the first grinder and the swing screen in sequence; the swing screen is provided with a swing screen coarse material discharge port, a swing screen intermediate material discharge port and a swing screen fine material discharge port, which are connected to the second grinder and the second hopper in sequence; a negative pressure pipe is connected above the second hopper, a negative pressure fan is provided on the negative pressure pipe, and the negative pressure pipe is connected to the first hopper; the negative electrode discharge port is connected to the copper hopper.

2. The pole piece recovery system according to claim 1, characterized in that: The first screening device is a drum screen or a vibrating screen, and the second screening device is a drum screen or a vibrating screen.

3. The pole piece recovery system according to claim 1, characterized in that: The crusher and the first pulverizer, the first pulverizer and the first screening device, and the second pulverizer and the second screening device are connected respectively through a feeding device, and the feeding device is selected from a screw feeder, a bucket elevator and / or a belt conveyor.

4. The pole piece recovery system according to claim 1, characterized in that: The sieve hole diameters of the first sieving device and the second sieving device are 0.15 mm.

5. The pole piece recovery system according to claim 1, characterized in that: The swing screen is provided with a large-aperture swing screen and a small-aperture swing screen. The aperture of the large-aperture swing screen is 5-10mm, and the aperture of the small-aperture swing screen is 0.15mm.

6. The pole piece recovery system according to claim 1, characterized in that: A filter is provided at the connection between the second hopper and the negative pressure pipe, and the pore size of the filter is 0.15 mm.

7. The pole piece recovery system according to claim 1, characterized in that: The first powder discharge port, the second powder discharge port, and the swing screen fine material discharge port are respectively connected to the black powder hopper; the swing screen coarse material discharge port is connected to the large particle size material hopper, and the second hopper is connected to the small particle size aluminum hopper.

8. A pole piece recycling method, characterized in that: The positive electrode sheet is recycled using the electrode sheet recycling system as described in any one of claims 1 to 7, comprising the steps of: (1) Turn on the negative pressure fan, then put the positive electrode sheet into the crusher to crush it to obtain the positive electrode material, send the positive electrode material to the first crusher for crushing, and send it to the first screening device for screening, discharge and collect the screened positive electrode black powder through the first powder material discharge port, and discharge the remaining positive electrode material through the first large particle size discharge port; (2) The positive electrode material discharged through the first large particle size discharge port is sequentially sent to the second pulverizer for crushing and sent to the second screening device for screening. The screened positive electrode black powder is discharged and collected through the second powder discharge port, and the remaining positive electrode material is discharged through the second large particle size discharge port and enters the first hopper; (3) The positive electrode discharge port is opened and the negative electrode discharge port is closed. The positive electrode material in the first hopper enters the first grinder through the positive electrode discharge port for grinding, and then enters the swing screen to be screened into large particles, medium particles and small particles. The large particles are discharged and collected through the coarse material discharge port of the swing screen, and the small particles are discharged and collected through the fine material discharge port of the swing screen. The medium particles enter the second grinder through the intermediate material discharge port of the swing screen for grinding, and then enter the second hopper; (4) Under the action of the negative pressure fan, the black powder in the second hopper is sucked into the negative pressure pipe and then sent to the first hopper for circulation treatment.

9. A method for recycling pole pieces, characterized in that: The negative electrode sheet is recycled using the electrode sheet recycling system as claimed in any one of claims 1 to 7, comprising the steps of: (i) The negative electrode sheet is put into a crusher to be crushed to obtain a negative electrode material, which is then sequentially sent to a first crusher for crushing and a first screening device for screening, and the screened negative electrode black powder is discharged and collected through a first powder material discharge port, and the remaining negative electrode material is discharged through a first large particle size discharge port; (ii) the negative electrode material discharged through the first large particle size outlet is sequentially sent to the second pulverizer for pulverization and sent to the second screening device for screening, the screened negative electrode black powder is discharged and collected through the second powder outlet, and the remaining negative electrode material is discharged through the second large particle size outlet and enters the first hopper; (iii) opening the negative electrode discharge port and closing the positive electrode discharge port, and discharging and collecting the negative electrode material in the first hopper through the negative electrode discharge port.

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