Negative pressure type sealed powder material feeding system

Abstract

The utility model relates to a negative pressure type sealed powder material feeding system, which is provided with a buffer tank (10), a mixing kettle (4) and a suction blowback device, the buffer tank (10) is fixedly connected with an opening part of the mixing kettle (4) through an asymptotic opening control valve (9), and the suction blowback device is connected with the buffer tank (10) through a control valve (9). The suction and blowback device is provided with a suction mechanism for negative pressure suction and a blowback mechanism for positive pressure blowback, a first dust collection port (40) is formed in an opening of the buffer tank (10) and is communicated with the suction mechanism, a second dust collection port (50) and a dust return port (60) are formed in an opening of the mixing kettle (4), and the dust return port (60) is communicated with the buffer tank (10). The second dust collection port (50) is communicated with the suction mechanism, and the dust return port (60) is communicated with the back flushing mechanism. The feeding system is suitable for self-weight blanking of powder materials such as active substances for electrodes of secondary batteries such as lithium ion secondary batteries, the feeding efficiency and precision are high, the loss is small, and the dust amount is small.

Description

Technical Field

[0001] The utility model relates to a novel automatic integrated negative pressure sealed powder material feeding system. Background Art

[0002] In the past, the feeding process before the mixing process of active materials for lithium secondary battery electrodes generally includes the following steps: first, weigh the stainless steel raw material barrel containing the active material, then move the stainless steel raw material barrel containing the active material to the feeding platform through a customized lifting and flipping integrated trolley, and then manually flip the stainless steel raw material barrel so that the active material can be fed from the stainless steel raw material barrel to the mixing kettle under the action of its own weight. After the feeding is completed, the stainless steel raw material barrel is weighed again, and the difference between the two weighings of the stainless steel raw material barrel is recorded as the actual utilization of the active material fed. Since part of the active material is lost in the form of dust and attached dust during the feeding process, there is a data deviation between the amount of active material calculated based on the feeding amount and the actual utilization of the active material, and there is also the problem of excessive environmental dust.

[0003] The operation time, labor intensity, management and logistics costs of the existing active material feeding and mixing processes are high, so it is hoped that the feeding and mixing processes can be carried out with an integrated automated production line. In this way, the use of general-purpose ton bags to package active material raw materials becomes an inevitable choice, and it is necessary to consider the space factors such as the floor height and area required for the feeding and mixing workshops of the automated production line. In addition, it is also necessary to consider the integrated distribution design of the automated production line. In addition, it is necessary to find solutions for the following issues in the feeding and mixing processes: how to reduce dust, active material loss and environmental dust during feeding, while accurately weighing the active materials fed and efficiently performing the mixing process.

[0004] In the prior art of the feeding and mixing process of powder materials, there are already literature reports on reducing dust, active material loss and environmental dust during feeding. CN115593983A discloses a mobile negative pressure protection device for feeding of pharmaceutical intermediates, which solves the technical problems of reducing the amount of dust generated during the feeding process, reducing the amount of loss of feeding, and reducing the adhesion of dust to the dust removal component. The mobile negative pressure protection device is characterized in that it includes a negative pressure feeding device, a mobile unit is arranged on the outside of the negative pressure feeding device, the negative pressure feeding device includes a feeding hopper, an inner sleeve is arranged inside the feeding hopper, a gas flow sensor is arranged on the inner top of the feeding hopper, a feeding pipe is arranged at the bottom end of the feeding hopper, a negative pressure inner core component composed of an inner tube and an outer tube is rotatably connected to the inner top of the feeding pipe, the top and bottom ends between the inner and outer tubes of the negative pressure inner core component are provided with rubber air guide blades, and the inner side wall of the top of the inner sleeve is provided with a suction A powder trough, a cleaning assembly is provided on the outer side of the inner sleeve; an electric push rod is provided on the top of the feeding hopper, a telescopic rod corresponding to the electric push rod is provided on the middle part of the inner side of the inner sleeve, shaft adapters are provided at the ends of the electric push rod and the telescopic rod respectively, and an upper rotating shaft is connected between the two shaft adapters, a spiral blade fixedly connected to the inner wall of the negative pressure inner core is provided in the middle part of the negative pressure inner core, a lower rotating shaft is provided in the middle part of the spiral blade, and a square seat is provided in the middle part of the top end of the lower rotating shaft, and a sliding groove slidably connected to the square seat is provided at the bottom end of the upper rotating shaft.

[0005] The above-mentioned document studies the topic of reducing dust, loss and environmental dust during the process of feeding of pharmaceutical intermediates in production, and designs a mobile negative pressure protection device.

[0006] However, the feeding and mixing process of active materials for secondary battery electrodes such as lithium-ion secondary batteries is significantly different from the feeding and mixing process of powder materials for pharmaceutical intermediate production in terms of materials, equipment and process requirements. It is necessary to develop a powder material feeding system suitable for the automated production of active materials for secondary battery electrodes such as lithium-ion secondary batteries, which has high feeding efficiency and accuracy, low loss and low dust. Utility Model Content

[0007] The utility model aims to provide a negative pressure sealed powder material feeding system which is suitable for the self-weight feeding of powder materials such as active materials for secondary battery electrodes such as lithium ion secondary batteries, and has high feeding efficiency and accuracy, low loss and low dust.

[0008] The gist of the utility model is as follows.

[0009] (1) A negative pressure sealed powder material feeding system, comprising a buffer tank, a kneading kettle and a suction backflush device, wherein the buffer tank is connected and fixed to the opening of the kneading kettle via an asymptotic opening control valve,

[0010] The suction backflush device comprises a suction mechanism for performing negative pressure suction and a backflush mechanism for performing positive pressure backflush.

[0011] The buffer tank has a first dust collection port opened on the top, and the first dust collection port is connected to the suction mechanism.

[0012] The mixing kettle has an opening with a second dust collecting port and a dust returning port, wherein the second dust collecting port is connected to the suction mechanism, and the dust returning port is connected to the back-blowing mechanism.

[0013] (2) According to the negative pressure sealed powder material feeding system described in (1) above, it also has an inflation device that is surrounded and arranged on the outer side surface of the opening of the buffer tank, and the inflation device has an inflation sleeve and an inflation and exhaust mechanism for inflating and exhausting the inflation sleeve.

[0014] (3) According to the negative pressure sealed powder material feeding system described in (2) above, the inflation and exhaust mechanism includes: an inflation and exhaust pipeline; a pressure reducing valve for adjusting and detecting the air pressure in the inflation and exhaust pipeline; and an electromagnetic valve for controlling inflation and exhaust.

[0015] (4) According to the negative pressure sealed powder material feeding system described in (1) or (2) above, a fixing device for fixing the bottom end of a ton bag containing powder material is provided at the opening of the buffer tank.

[0016] (5) According to the negative pressure sealed powder material feeding system described in (1) or (2) above, the kneading kettle and the kettle cover are sealed by a rubber material attached to the outer surface of the kneading kettle.

[0017] (6) According to the negative pressure sealed powder material feeding system described in (1) or (2) above, the suction mechanism includes a dust collector, a pipeline with a valve, and a filter unit.

[0018] (7) According to the negative pressure sealed powder material feeding system described in (1) or (2) above, the backflush mechanism includes a positive pressure power source, a pipeline with a valve, and a filter unit.

[0019] (8) According to the negative pressure sealed powder material feeding system described in (1) or (2) above, the progressive opening control valve is arranged at the outlet of the buffer tank, the outlet of the buffer tank and the progressive opening control valve are sealed by a flange plane connection, and a sealing flange is arranged at the outlet of the progressive opening control valve, and the sealing flange is connected to the kettle cover of the mixing kettle by rubber material.

[0020] (9) According to the negative pressure sealed powder material feeding system described in (1) or (2) above, it also has a weighing device for weighing the kneading kettle and its contents, and the weighing device is located below the kneading kettle.

[0021] (10) According to the negative pressure sealed powder material feeding system described in ((1) or (2) above, the powder material is an active material for secondary battery electrodes.

[0022] Utility Model Effect

[0023] The utility model can provide a negative pressure sealed powder material feeding system suitable for self-weight feeding of powder materials such as active materials for secondary battery electrodes such as lithium ion secondary batteries, and has high feeding efficiency and accuracy, low loss and low dust. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of an implementation of the negative pressure sealed powder material feeding system of the utility model.

[0025] Figure 2 yes Figure 1 Schematic diagram of a specific example of the usage state of the main part of the negative pressure sealed powder material feeding system shown in FIG.

[0026] Figure 3A and Figure 3B They are Figure 1 A cross-sectional schematic diagram and a top view of a specific example of the configuration state of the air inflation sleeve of the negative pressure sealed powder material feeding system shown in FIG.

[0027] Figure 4 It is a schematic diagram of the working status of the suction backflush device.

[0028] Figure 5 It is a schematic cross-sectional view of a filter unit of a suction backflush device.

[0029] Figure 6 yes Figure 1 A cross-sectional schematic diagram of a specific example of a weighing device of a negative pressure sealed powder material feeding system shown in FIG.

[0030] Figure 7 It is a schematic diagram of the results of 30 feeding experiments of the negative pressure sealed powder material feeding system of the embodiment.

[0031] Figure 8 It is a schematic diagram of the feeding and kneading process of the powder material feeding system of the comparative example. DETAILED DESCRIPTION

[0032] The specific implementation methods and embodiments of the utility model will be described in detail below in conjunction with the accompanying drawings. The described implementation methods and embodiments are only exemplary and can take a variety of forms. In addition, the drawings disclosed in this specification are schematically illustrated in principle. That is, the size ratios on the drawings may not be consistent with the actual size ratios, and the size ratios between the drawings may not be consistent.

[0033] The utility model relates to a negative pressure sealed powder material feeding system (hereinafter sometimes referred to as "the feeding system of the utility model"), which comprises a buffer tank, a kneading kettle and a suction backflush device, wherein the buffer tank is connected and fixed to the opening of the kneading kettle via an asymptotic opening control valve.

[0034] The suction backflush device comprises a suction mechanism for performing negative pressure suction and a backflush mechanism for performing positive pressure backflush.

[0035] The buffer tank has a first dust collection port opened on the top, and the first dust collection port is connected to the suction mechanism.

[0036] The mixing kettle has an opening with a second dust collecting port and a dust returning port, wherein the second dust collecting port is connected to the suction mechanism, and the dust returning port is connected to the back-blowing mechanism.

[0037] From the perspective of ease of configuration and convenience of operation, it is preferred that the first dust collecting port is opened on the side of the buffer tank, and the second dust collecting port and the dust return port are opened on the lid of the mixing kettle, respectively.

[0038] For the sake of sealing and convenience of feeding, the feeding system of the utility model preferably also has an air expansion device arranged around the outer side of the opening of the buffer tank, and the air expansion device has an air expansion sleeve and an inflation and exhaust mechanism for inflating and exhausting the air expansion sleeve. The air expansion sleeve is sealed against the fixing part of the opening by inflation and expansion. Generally speaking, the inflation and exhaust mechanism includes: an inflation and exhaust pipeline; a pressure reducing valve for adjusting and detecting the air pressure in the inflation and exhaust pipeline; and a solenoid valve for controlling inflation and exhaust.

[0039] The inflatable sleeve is preferably arranged concentrically with the buffer tank. The inflatable sleeve is made of a rubber material such as silicone rubber. The inflatable gas can be an inactive gas such as air, and is preferably air in terms of easy acquisition and low cost.

[0040] The kneading kettle and the kettle cover are preferably sealed by a rubber material such as silicone rubber attached to the outer surface of the kneading kettle.

[0041] The feeding system of the utility model preferably utilizes a ton bag filled with powder material to supply the powder material to the buffer tank, and a fixing piece for fitting and fixing the bottom end of the ton bag filled with powder material is provided at the opening of the buffer tank.

[0042] The above-mentioned ton bag preferably includes an outer bag and an inner bag. Generally speaking, the outer bag is a plastic bag made of plastic material, and the inner bag is an aluminum-plastic bag made of aluminum-plastic material. The outer bag and the inner bag are mutually nested, and the parts other than the bottom ends of each of them can be bonded together. The powder material is contained in the inner bag, so that the powder material is completely isolated from the external environment and kept clean. Before the start of feeding, the bottom end of the inner bag of the ton bag is first nested on the fixing part of the opening of the buffer tank, and then the inflation sleeve is inflated and tightened, and then the bottom end of the inner bag of the ton bag is fixed to the fixing part of the opening of the buffer tank. Generally speaking, a precision pressure reducing valve for adjusting and detecting the air pressure is provided in the inflation and exhaust pipeline of the inflation device to prevent the inflation sleeve from rupturing due to excessive pressure.

[0043] The ton bag is lifted by using the slings fixed on the outer surface thereof. The bottom end of the aluminum-plastic bag as the inner bag is in a folded state, and the folded length is, for example, 800 mm. The thickness of the aluminum-plastic bag is, for example, 122 μm.

[0044] The suction backflush device is an important device for reducing dust and feeding loss. The suction mechanism mainly includes a dust collector, a pipeline with a valve, and a filter unit. The suction mechanism is used to suck the dust generated during feeding and retain it in the filter unit. The backflush mechanism mainly includes a positive pressure power source, a pipeline with a valve, and a filter unit. The backflush mechanism is used to backflush the dust trapped in the filter unit into the mixing kettle through the dust return port.

[0045] The progressive opening control valve is arranged at the outlet of the buffer tank. Preferably, the outlet of the buffer tank is sealed with the butterfly valve through a flange plane connection. A sealing flange is arranged at the outlet of the progressive opening control valve, and the sealing flange is connected to the kettle cover of the mixing kettle through a rubber material such as silicone rubber.

[0046] The opening adjustment of the asymptotic opening control valve is used to control the speed of feeding to prevent impact and excessive dust. The control valve is immediately closed when backflush begins. The asymptotic opening control valve is preferably an adjustable opening butterfly valve.

[0047] According to the feeding system of the utility model, the shape of the buffer tank is not particularly limited, for example, it can be a cylindrical container, or a sloped container that is large in the middle and small at both ends.

[0048] According to the feeding system of the utility model, as a means to reduce dust and material loss and improve material dropping accuracy, negative pressure suction is used to assist the material dropping while carrying out the material dropping by its own weight. In addition, in order to ensure the negative pressure state, the connection parts of the ton bag, the buffer tank and the mixing kettle are all sealed.

[0049] The feeding system of the utility model also preferably has a weighing device for weighing the mixing kettle and its content, and the weighing device is located below the mixing kettle.

[0050] The powder material is preferably an active material for a secondary battery electrode, such as a positive electrode active material or a negative electrode active material for a lithium ion secondary battery. The secondary battery is not particularly limited and may be a lithium ion secondary battery, a nickel-hydrogen secondary battery, a nickel-cadmium secondary battery, a lead-acid secondary battery, etc.

[0051] Hereinafter, for the sake of simplicity, the powder material is sometimes directly referred to as an active substance.

[0052] The feeding system of the utility model preferably utilizes a lifting mechanism such as a trolley hoist to lift and move the ton bag left and right. The trolley hoist is a light and small lifting equipment with the characteristics of small size, light weight, simple operation and convenient use. Its lifting weight and lifting height are suitable for the powder material feeding system of the utility model.

[0053] The feeding system of the utility model also preferably has a support platform with a hollow part for supporting the ton bag during feeding. The ton bag is placed on the support platform before feeding, and the bottom end of the ton bag is exposed from the hollow part of the support platform. The tether at the bottom end of the outer bag is untied and the bottom end of the folded inner bag is pulled out, and the plastic sealing part of the bottom end of the inner bag is cut off manually. The bottom end of the aluminum-plastic bag after the plastic sealing part is cut off is expanded as a cylinder and put on the fixing part of the opening of the buffer tank, and then the inflatable sleeve is inflated and tightened, and then the bottom end of the aluminum-plastic bag is fixed to the fixing part.

[0054] Figure 1 The schematic diagram of one embodiment of the negative pressure sealed powder material feeding system of the utility model is shown in FIG. The feeding system can realize full sealing of the feeding process and self-weight dropping of the materials.

[0055] Figure 1 The negative pressure sealed powder material feeding system mainly includes the following devices:

[0056] A trolley hoist 22, which is a lifting mechanism for lifting and lowering the ton bag 23 and moving it left and right;

[0057] A pallet 24, which is a tool for carrying the bulk bag 23;

[0058] A support platform 14 having a hollow portion, which supports the bottom end of the ton bag 23 when feeding;

[0059] The gas expansion device comprises a gas expansion sleeve 13 for fixing the bottom end of the inner bag of the ton bag to the fixing piece 30 of the opening of the buffer tank by expansion, a gas filling pipeline, a pressure reducing valve 11 for precisely adjusting and detecting the air pressure in the gas filling pipeline, and a solenoid valve 12 for controlling the inflation and exhaust of the gas expansion sleeve 13;

[0060] The buffer tank 10 is used to contain the active material fed from the ton bag and to prevent impact, and a first dust collecting port 40 is opened on the side thereof;

[0061] A mixing kettle 4, which is a container for storing and mixing the active substances fed;

[0062] A kettle cover 6, which seals the kettle opening of the mixing kettle 4 and is provided with a second dust collecting port 50 and a dust returning port 60;

[0063] Cylinder unit 8: It is the driving component that makes the kettle cover rise and fall;

[0064] The adjustable opening butterfly valve 9 controls and adjusts the amount of active material in the buffer tank 10 fed to the mixing kettle 4, and adjusts the opening according to the weight of the active material in the ton bag;

[0065] The flexible connection 26 is connected to the kettle cover 6 and conveys the active substance. The flexible connection 26 is made of metal material such as SUS304. The contact part between the flexible connection 26 and the kettle cover 6 is preferably embedded with rubber material such as silicone rubber to play a role of buffering and wear resistance.

[0066] The dust collector 25 is a power source for generating suction negative pressure in the buffer tank 10 and the mixing kettle 4;

[0067] The weighing device comprises: a load platform 3 docked with a mobile track in a factory building and used for carrying a kneading kettle 4, a cylinder 1 used for lifting the load platform 3 up and down, and a floor scale 2 for weighing the weight of the kneading kettle 4 and its contents.

[0068] Solenoid valve 18, which is a switch for controlling the blowing of nitrogen or air;

[0069] The solenoid valve 19 is a switch for controlling the negative pressure suction in the buffer tank 10 and the mixing kettle 4;

[0070] The solenoid valve 28 is a switch for controlling the negative pressure suction in the buffer tank 10;

[0071] The solenoid valve 29 is a switch for controlling back-blowing into the buffer tank 10;

[0072] Positive pressure power source 35: it is a power source for blowing nitrogen or air at positive pressure to generate back-blowing positive pressure;

[0073] Pipeline 17, which is a pipeline for conveying nitrogen or air from positive pressure power source 35; and

[0074] The pipeline 20 and the pipeline 27 are pipelines for conveying dust.

[0075] like Figure 1 As shown in the figure, the support platform 14 is higher than the opening of the buffer tank 10, and the distance between the two is, for example, 200 to 400 mm. Such an arrangement facilitates the untying of the outer bag of the ton bag 23. The inflatable sleeve 13 is arranged concentrically with the opening of the buffer tank 10. In the natural state without inflation, there is a certain gap between the inflatable sleeve 13 and the outer diameter of the opening of the buffer tank 10, for example, 30 mm. This gap enables the staff to manually fit the bottom end of the inner bag 16 of the ton bag 23 onto the fixing part 30 of the opening of the buffer tank 10. The fixing part 30 is usually in the shape of a ring, that is, a fixing ring. A filter screen for filtering and dispersing powder materials is provided at the interface between the fixing part and the opening of the buffer tank, and the filter screen is made of plastic materials such as PTFE. The expandable stroke of the inflatable sleeve 13 is, for example, 20 to 50 mm. After the bottom end of the inner bag 16 is mounted on the fixing piece 30 of the opening of the buffer tank 10, the signal of the sensor 15 for detecting whether the inner bag is mounted will be connected. At this time, the solenoid valve 12 opens to inflate the inflatable sleeve 13. A precision pressure reducing valve 11 is provided in the inflatable pipeline to adjust and detect the air pressure to prevent the inflatable sleeve from rupturing due to excessive pressure. The normal inflatable air pressure is in the range of 0.05 to 0.2 MPa. When the air pressure is 0.05 MPa, the tightening force of the inner bag is 420N. A pressure sensor is provided at the outlet of the precision pressure reducing valve, which will detect abnormal conditions and issue an alarm when the inflatable sleeve 13 is damaged.

[0076] After the mixing kettle 4 is lowered into place, the sensor 5 signal is connected, that is, the sensor 5 detects that the kettle is in place, and after the kettle cover is lowered into place, the sensor 7 signal is connected, that is, the sensor 7 detects that the kettle cover is in place.

[0077] The suction mechanism includes a dust collector 25, a pipeline with a valve, and a filter unit 21. The back-blowing mechanism includes a positive pressure power source 35, a pipeline with a valve, and a filter unit 21. The positive pressure power source 35 can be high-purity nitrogen with an air pressure of 0.2 to 0.5 MPa or compressed air treated with filtered water and oil. The suction mechanism and the back-blowing mechanism are opened and used successively. The filter unit of the suction mechanism and the back-blowing mechanism is shared, and the pipeline of the suction mechanism and a part of the pipeline of the back-blowing mechanism are shared, and the shared pipeline is switched by a solenoid valve. A first dust collecting port 40 is opened on the side of the buffer tank 10, and a second dust collecting port 50 and a dust return port 60 (i.e., a back-blowing dust collecting port) are opened on the kettle cover 6. The first dust collecting port, the second dust collecting port and the dust return port are each connected to the filter unit 21 through a pipeline with a valve. A composite membrane filter bag is arranged inside the filter unit 21, and its filtration efficiency for particles with a diameter of 10 μm or more is 99%. The membrane filter bag is preferably a hollow cylindrical form with one end closed.

[0078] The suction mechanism is immediately turned on after the feeding of the ton bag begins, and the solenoid valve 28 and the solenoid valve 19 are opened first, and then the dust collector 25 is turned on for suction operation, so that the dust formed in the buffer tank and the kneading kettle is sucked and retained in the filter unit 21. At the end of the feeding, the suction mechanism is turned off, the dust collector 25 is turned off first, and then the solenoid valve 19 is turned off, and then the solenoid valve 28 is turned off, and then the backflush mechanism is turned on, the solenoid valve 18 is opened, and then the positive pressure power source 35 delivers, for example, high-purity nitrogen (factory-made high-pressure liquid nitrogen with a water content of 1ppm) with a pressure of 0.2 to 0.5MPa or compressed air treated with filtered water and oil through the pipeline 17, and the active substances retained in the filter unit 21 are backflushed into the kneading kettle 4 by such nitrogen or compressed air.

[0079] Figure 2 yes Figure 1 Schematic diagram of a specific example of the usage state of the main part of the negative pressure sealed powder material feeding system shown in FIG. Figure 2 Each tag in Figure 1 The same symbols in the table have exactly the same meaning. Figure 2 As shown, the ton bag and the buffer tank are expanded and sealed by an inflation sleeve 13; an adjustable opening butterfly valve 9 is provided at the outlet of the buffer tank, and the buffer tank and the butterfly valve are connected and sealed by a flange plane; a sealing flange is provided at the outlet of the butterfly valve and is connected and sealed with the kettle cover by a soft connection with a rubber material such as silicone rubber; the kettle cover is made of a circular plate made of stainless steel or other materials as a whole, and a stainless steel plate with a thickness of, for example, 2mm is welded on its outer circumference to form a circumferential sealing edge of the kettle cover, and silicone rubber or other rubber materials are attached to the contact portion between the stainless steel circular plate and the circumference of the mixing kettle to ensure the sealing between the kettle cover and the mixing kettle.

[0080] After the signal of sensor 15 is connected, the air pressure of the inflatable sleeve is greater than the preset value, for example 0.05Mpa, and the inflatable device enters automatic operation. The air pressure of the inflatable sleeve is maintained until the weighing of the floor scale 2 reaches the predetermined weight. After the weighing of the floor scale 2 reaches the predetermined weight signal and the stop signal of the dust collector 25 are connected, the inflatable device is stopped and the inflatable sleeve is released.

[0081] Figure 3A and Figure 3B They are Figure 1 The cross-sectional schematic diagram and top view schematic diagram of a specific example of the configuration state of the air expansion sleeve of the negative pressure sealed powder material feeding system shown in FIG. Figure 3A and Figure 3B As shown, the inflatable sleeve 13 is concentrically arranged with the opening of the cache tank 10. In the natural state without inflation, there is a certain gap between the inflatable sleeve 13 and the outer diameter of the opening of the cache tank 10, for example, 30 mm. This gap enables the staff to manually fit the bottom end of the inner bag of the ton bag onto the fixing member 30 of the opening of the cache tank 10. The fixing member 30 is usually in the shape of a ring, i.e., a fixing ring. In addition, the cache tank 10 can be selected in different shapes according to actual needs. It can be a cylindrical container or a sloped container with a large middle and small ends.

[0082] Figure 4 It is a schematic diagram of the working state of the suction backflush device. When the weight difference measured by the weighing device, i.e., the feed loss, is greater than a predetermined value, the backflush mechanism of the suction backflush device is activated to backflush the active material trapped in the filter unit into the mixing kettle until the weight difference, i.e., the feed loss, is lower than a predetermined value. Figure 4 Each tag in Figure 1 The same symbols in the table have exactly the same meaning. Figure 4 As shown, during back-blowing, the pressure change when the mixing kettle is switched from negative pressure to positive pressure should be avoided to avoid abnormal weighing data. During back-blowing, the solenoid valve 19 and the solenoid valve 28 are cut off, and the solenoid valve 18 and the solenoid valve 29 are connected, and the active material trapped in the filter unit is back-blown back to the mixing kettle. At the same time, the mixing kettle is made non-positive pressure. The non-positive pressure is due to the high pressure (for example, the air pressure is 0.2-0.5MPa) and small flow rate of the nitrogen gas blown into the pipeline 17, while the nitrogen gas pressure in the pipeline 27 is low and its flow rate is equivalent to the positive pressure of nitrogen gas. Therefore, even if the nitrogen gas is blown into the mixing kettle at a positive pressure, a positive pressure environment will not be formed, that is, non-positive pressure. The nitrogen gas can also be replaced by compressed air that has been filtered, filtered, and treated with water and oil.

[0083] Figure 5 It is a cross-sectional schematic diagram of the filter unit of the suction backflush device. Figure 5As shown, a retention container is provided in the dust collection pipeline, and a filter unit is designed in the container. Specifically, the filter unit includes a container 80 and a filter bag 81 fixed in the container 80 by a pressure ring 70 or the like via O-rings 75 and 76, and the container 80 is provided with a suction inlet 85 and a suction backflush interface 86 on the surface side and the back side of the filter bag, respectively. Preferably, the filter bag is an ultrafine particle composite membrane filter bag, which is cylindrical and one end of which is open, and a pipeline connection port is also designed in the middle part, and the open end of the filter bag is pressed together by a sealing pressure ring.

[0084] Figure 6 yes Figure 1 A cross-sectional schematic diagram of a specific example of a weighing device of a negative pressure sealed powder material feeding system shown in the figure. Due to height space limitations, the weighing device's scale 2 is set below the ground, and a track with the same width as the moving track of the mixing kettle 4 in the workshop is set on the load platform 3. During weighing, the load platform 3 and the mixing kettle 4 are lowered as a whole to the scale 2 for planar weighing. After the mixing kettle 4 is lowered into place, the sensor 5 signal is connected, that is, the sensor 5 detects that the kettle is in place. After the kettle cover is lowered into place, the sensor 7 signal is connected, that is, the sensor 7 detects that the kettle cover is in place. At this time, the solenoid valve 19 is opened, and the dust collector 25 is running. The scale 2 is automatically peeled and zeroed in this state. Because the weight of the kettle cover and the traction of the soft connection will affect the weight, the scale 2 is reset to zero after ensuring that all components are in working condition. The load platform 3 can be designed with eyebolts 56 for lifting during maintenance. The load platform 3 is lifted up and down by two oil cylinders 1 symmetrically arranged on both sides relative to the center, but the load platform 3 and the oil cylinder 1 are not fixedly connected, so the load platform 3 and the oil cylinder 1 can be completely separated when necessary. The oil pump 55 for controlling the oil amount in the oil cylinder 1 is arranged adjacent to the removable cover plate to save floor space. The weighing device can weigh every 8 to 12 minutes, and the mixing time can be 1.5 to 2 hours. The feeding can also be carried out in multiple times, that is, the feeding interval can be 20 to 90 minutes.

[0085] The opening of the butterfly valve 9 can be opened in a dynamic and adjustable manner. The opening of the butterfly valve 9 is controlled according to the overall weight of the ton bag, the weight of the active substance contained therein, and the weighing weight range of the scale 2 to reduce the impact load of the scale 2.

[0086] After the active material accurately weighed as described above is added to the mixing kettle, a conductive material, a binder, a thickener and / or a solvent may be added according to actual needs, and these materials are fully mixed in the mixing kettle once or several times to form an active material for a secondary battery electrode, for example, an active material for a positive electrode or an active material for a negative electrode of a lithium ion secondary battery. The types and amounts of the active materials, conductive materials, binders, thickeners and / or solvents mentioned above are not particularly limited, and may be those commonly used in secondary batteries such as lithium ion secondary batteries.

[0087] Example

[0088] The structural configuration and operation steps of the negative pressure sealed powder material feeding system of this embodiment are based on Figure 1 to Figure 6 The following only describes the structural configuration and specific aspects and specific values ​​of the operation steps of the negative pressure sealed powder material feeding system in this embodiment. For other contents, please refer to the previous description.

[0089] The negative pressure sealed powder material feeding system of this embodiment includes a trolley-type rail hoist lifting mechanism, an air expansion device, a buffer tank, a progressive opening butterfly valve, a ton bag support platform, a kettle cover lifting unit, a negative pressure suction mechanism, a mixing kettle, flexible soft connections of rubber materials such as silicone rubber, an underground weighing scale, a load platform lifting mechanism, a backblowing mechanism, a precision pressure reducing valve, an aluminum-plastic bag detection sensor and a PTFE filter, etc.

[0090] The manual operation uses a trolley hoist to move the ton bag from the ground to the ton bag support platform, and then the bottom end of the inner bag of the ton bag is opened and mounted on the fixing part of the opening of the buffer tank. At this time, the bottom end of the inner bag remains folded. Dry compressed air is introduced into the inflation sleeve of the inflation device to inflate the inflation sleeve, and then the entire circumference of the bottom end of the inner bag is tightly fixed on the fixing part of the opening of the buffer tank. At the same time, the buffer tank forms a negative pressure space under the action of the negative pressure suction mechanism. The manual operation of the trolley hoist is to rise, and the bottom end of the ton bag gradually separates from the ton bag support platform. The active material in the ton bag automatically falls into the buffer tank under the action of its own weight and negative pressure. According to the weight measured by the weighing device, the gradual opening degree of the butterfly valve is controlled to realize the automatic feeding of the active material in the buffer tank into the mixing kettle.

[0091] The folded length of the bottom end of the aluminum-plastic bag as the inner bag of the ton bag is 800 mm, and the thickness of the aluminum-plastic bag is 122 μm. The support platform 14 is 300 mm above the mouth of the buffer tank 10.

[0092] like Figure 2As shown, the kettle cover is made of SUS304 stainless steel circular plate, and a 2mm thick SUS304 stainless steel plate is welded on its outer circumference to form the circumferential sealing edge of the kettle cover. Silicon rubber and other rubber materials are attached to the contact part between the SUS304 stainless steel circular plate and the circumference of the mixing kettle to ensure the sealing between the kettle cover and the mixing kettle. The opening of the butterfly valve 9 can be adjusted with the movement. The weighing device is used to weigh every 8 minutes. The overall weight of the ton bag is 450Kg. When the weight measured by the scale 2 is in the range of 0 to 400Kg, the opening of the butterfly valve 9 is 60%, which can reduce the impact load on the scale 2. When the weight measured by the scale 2 is in the range of 400 to 440Kg, the opening of the butterfly valve 9 is 80%, and when the weight measured by the scale 2 is in the range of 440 to 450Kg, the opening of the butterfly valve 9 is 100%. Close the butterfly valve 9 immediately when the backflush starts.

[0093] As a means of ensuring sealing and reducing dust, such as Figure 3A and Figure 3B As shown in the figure, the inflatable sleeve is arranged concentrically with the buffer tank. The main component of the inflatable sleeve is a closed rubber material sleeve such as silicone rubber, which can expand along the diameter direction under an air pressure of more than 0.05MPa. After expansion, the outer diameter of the fixing part 30 of the opening of the buffer tank is 30mm larger than the outer diameter of the fixing part 30, thereby ensuring that the mouth of the bottom end of the inner bag of the ton bag can be tightly pressed and fixed on the fixing part 30 of the opening of the buffer tank.

[0094] As a means of reducing dust and feeding loss, the following Figure 4 When the weight difference measured by the scale, i.e. the feed loss, is greater than 2Kg, the backflush function is activated to backflush the active material in the filter bag into the mixing kettle until the weight difference, i.e. the feed loss, is less than 0.7Kg / 450Kg.

[0095] The weighing device of this embodiment is as follows Figure 6 As shown. The upper load limit of the platform weighing is 1500Kg, and the accuracy is 0.1Kg. The oil pump 55 for controlling the amount of oil in the oil cylinder is arranged adjacent to the removable cover plate, saving 500mm of ground space. The floor scale 2 is arranged below the ground, and the mixing kettle 4 is moved in the workshop by rail. The upper plane of the load platform 3 is provided with a track with the same width as the moving track of the mixing kettle 4 in the workshop. When weighing, the load platform 3 and the mixing kettle 4 are lowered as a whole to the upper plane of the floor scale 2 for weighing. There is no fixed connection between the liftable oil cylinder 1 and the load platform 3. The end of the oil cylinder 1 is a spherical structure, and the corresponding part of the load platform 3 is a recessed design matching the spherical surface 2. When the oil cylinder 1 is lowered, the load plane of the floor scale is 10mm higher than the spherical end of the oil cylinder 1, ensuring that the oil cylinder 1 has no effect on the measured weight of the floor scale 2 during weighing.

[0096] After the mixing kettle 4 is in place, the sensor 5 signal is connected, and the oil cylinder 1 is lowered into place. Figure 1The cylinder unit 8, which is the driving component for the kettle cover to rise and fall, descends. After the kettle cover is in place, the sensor 7 signal is connected, and the solenoid valve 19 is opened, and the dust collector 25 is running. Under this state, the floor scale 2 automatically peels and returns to zero. Because the weight of the kettle cover and the traction of the soft connection will affect the weight, the control surface must ensure that all parts are in working condition to return the floor scale 2 to zero.

[0097] According to the negative pressure sealed powder material feeding system of this embodiment, 30 feeding experiments were carried out by using a ton bag with an active material mass of 450Kg. The results showed that the actual weight of the active material mass fed into the mixing kettle was within the range of 449.95Kg to 450.15Kg after weighing. Figure 7 shown. Figure 7 It is a schematic diagram of the results of 30 feeding experiments of the negative pressure sealed powder material feeding system of the embodiment.

[0098] After the above tests, the negative pressure sealed powder material feeding system of this embodiment achieved the following results and effects:

[0099] 1. Combined with the universal ton bag material packaging, vertical space distribution can be achieved within a 3.7m height space using a trolley hoist, weight drop and weighing device.

[0100] 2. The entire circumference of the aluminum-plastic bag opening of the inner bag of the ton bag is fixed to the fixing piece of the opening of the buffer tank by the air expansion sleeve. The expansion force of the air expansion sleeve with a circumference of 1400mm is about 420N.

[0101] 3. The dust volume in the surrounding environment during feeding is 60000Pc / m 3 about.

[0102] 4. The feeding operation time is 10 minutes / 450Kg, and the loss after feeding is about 0.7Kg / 450Kg.

[0103] Comparative Example

[0104] Figure 8 Schematic diagram of the feeding and mixing process of the powder material feeding system of the comparative example. Figure 8As shown, two stainless steel raw material barrels containing 225 kg of active material are used to manually feed into the mixing kettle in two times, that is, the total amount of active material fed is 450 kg. Before feeding, the stainless steel raw material barrel containing 225 kg of active material is weighed, and then the stainless steel raw material barrel containing active material is moved to the feeding platform through a customized lifting and flipping integrated trolley. A negative pressure suction cover is provided on the platform. When the stainless steel raw material barrel is higher than the feeding port, the stainless steel raw material barrel is manually flipped clockwise to about 225°, and the active material is fed from the stainless steel raw material barrel to the mixing kettle under the action of its own weight. After the feeding is completed, the stainless steel raw material barrel is returned to 0°, that is, it is in the vertical position. After the feeding is completed, the empty barrel of the stainless steel raw material barrel is weighed, and the difference between the stainless steel raw material barrels weighed twice before and after is recorded as the amount of active material fed. The feeding operation steps of the second barrel are exactly the same as those of the first barrel, and finally the predetermined 450 kg of active material feeding is achieved. After the materials are added, they are fully kneaded in a kneading kettle to obtain a kneaded active material.

[0105] After the above tests, the feeding and mixing system of this comparative example achieved the following results and effects:

[0106] 1. The dust of active material powder is large when feeding, which is 800000Pc / m 3 ;

[0107] 2. The negative pressure suction loss during feeding is 2Kg / 450Kg;

[0108] 3. The residual amount of feed is 0.5Kg / 450Kg;

[0109] 4. Part of the handling work is done manually, which is labor-intensive and the feeding time is 40 minutes / 450Kg.

[0110] It should be noted that in this comparative example, the feeding weight depends on manual recording of the weight difference before and after, which has low accuracy.

[0111] The present invention is described above with respect to the currently preferred embodiments and examples, but such disclosures should not be interpreted as limiting. Various modifications and changes are obvious to those skilled in the art of the present invention by reading the above disclosures. Therefore, the appended claims should be understood to include all modifications and changes without departing from the true spirit and scope of the present invention.

[0112] Industrial Applicability

[0113] The negative pressure sealed powder material feeding system of the utility model can be applied to the feeding of powder materials such as active materials for secondary battery electrodes such as lithium ion secondary batteries, can drop materials by their own weight, and has high feeding efficiency and accuracy, low loss and little dust.

Claims

1. A negative pressure sealed powder material feeding system, which has a buffer tank, a mixing kettle and a suction backflush device, wherein: The buffer tank is connected and fixed to the opening of the kneading kettle via a gradual opening control valve. The suction backflush device comprises a suction mechanism for performing negative pressure suction and a backflush mechanism for performing positive pressure backflush. The buffer tank has a first dust collection port opened on the top, and the first dust collection port is connected to the suction mechanism. The mixing kettle has an opening with a second dust collecting port and a dust returning port, wherein the second dust collecting port is connected to the suction mechanism, and the dust returning port is connected to the back-blowing mechanism.

2. According to the negative pressure sealed powder material feeding system according to claim 1, it also has an inflation device which is arranged around the outer side surface of the opening of the buffer tank, and the inflation device has an inflation sleeve and an inflation and exhaust mechanism for inflating and exhausting the inflation sleeve.

3. The negative pressure sealed powder material feeding system according to claim 2, wherein: The inflation and exhaust mechanism comprises: an inflation and exhaust pipeline; a pressure reducing valve for adjusting and detecting the air pressure in the inflation and exhaust pipeline; and an electromagnetic valve for controlling inflation and exhaust.

4. The negative pressure sealed powder material feeding system according to claim 1 or 2, wherein: A fixing piece for fitting and fixing the bottom end of a ton bag filled with powder material is arranged at the opening of the buffer tank.

5. The negative pressure sealed powder material feeding system according to claim 1 or 2, wherein: The mixing kettle and the kettle cover are sealed by a rubber material attached to the outer surface of the mixing kettle.

6. The negative pressure sealed powder material feeding system according to claim 1 or 2, wherein: The suction mechanism comprises a dust collector, a pipeline with a valve, and a filter unit.

7. The negative pressure sealed powder material feeding system according to claim 1 or 2, wherein: The backflush mechanism comprises a positive pressure power source, a pipeline with a valve, and a filter unit.

8. The negative pressure sealed powder material feeding system according to claim 1 or 2, wherein: The progressive opening control valve is arranged at the outlet of the buffer tank, and the outlet of the buffer tank is sealed with the progressive opening control valve through a flange plane connection. A sealing flange is arranged at the outlet of the progressive opening control valve, and the sealing flange is connected to the kettle cover of the mixing kettle through rubber material.

9. The negative pressure sealed powder material feeding system according to claim 1 or 2, further comprising a weighing device for weighing the mixing kettle and its contents, wherein the weighing device is located below the mixing kettle.

10. The negative pressure sealed powder material feeding system according to claim 1 or 2, wherein: The powder material is an active material for secondary battery electrodes.

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