Lithium-ion secondary battery electrode additive powder measuring device equipped with two rows of screws

Abstract

The present invention relates to a weighing device for lithium-ion secondary battery electrode additive powder equipped with a two-row screw, and more specifically, to a weighing device for lithium-ion secondary battery electrode additive powder that can prevent bridging or rat-hole phenomena occurring during the weighing process of powder having particle sizes ranging from hundreds of nanometers to several micrometers, particularly lithium-ion secondary battery electrode additive powder, which is ground using a jet mill, while simultaneously preventing the inflow of magnetic foreign substances into the powder and drastically shortening the weighing time of the ground powder. A lithium-ion secondary battery electrode additive powder weighing device equipped with a two-row screw according to the present invention comprises: a frame; a hopper installed on the upper part of the frame for feeding and storing crushed powder; two conveying sections installed to communicate with the lower part of the hopper and having a rotating screw installed inside that is rotatably installed across the hopper; a clamp section installed at one end of each of the conveying sections for fixing a packaging bag and two weighing sections for measuring the weight of the packaging bag fixed to the clamp section.

Description

Technology Field

[0001] The present invention relates to a weighing device for lithium-ion secondary battery electrode additive powder equipped with a two-row screw, and more specifically, to a weighing device for lithium-ion secondary battery electrode additive powder that can prevent bridge or rat hole phenomena occurring during the weighing and packaging process of crushed powder having particle sizes ranging from hundreds of nanometers to several micrometers, particularly lithium-ion secondary battery electrode additive powder, which is crushed using a jet mill, while simultaneously preventing the inflow of magnetic foreign substances into the powder and drastically shortening the weighing time of the crushed powder. Background Technology

[0002] Recently, as electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles have become widely adopted and their specifications and performance have advanced, the demand for high-performance batteries with large capacity and high output characteristics is increasing. Accordingly, various attempts are being made to improve the energy density of batteries.

[0003] Amidst these efforts, research and development on lithium-ion secondary batteries with high energy density and excellent stability are actively underway, and interest in lithium-ion secondary batteries using high-nickel cathode materials is particularly increasing.

[0004] Although high-nickel cathodes can provide high energy density, they have the problem of degradation and capacity reduction during charging and discharging due to structural instability, and a high possibility of thermal runaway, especially in high-temperature environments.

[0005] Although various cathode active materials are used to address the problems of these high-nickel materials, cathode active materials alone cannot completely resolve the structural stability and degradation issues of high-nickel cathode materials.

[0006] Therefore, various additives are doped into the cathode active material to further enhance its structural stability and prevent degradation issues. Cathode active material additives strengthen the structure of the material, preventing deformation or decomposition during charging and discharging, and enabling the secondary battery to maintain stable performance even at high temperatures.

[0007] Boric acid (H3BO3), tungsten oxide (WO3), cobalt hydroxide (Co(OH)2), and yttrium oxide (Y2O3) are used as additives for the cathode active material of lithium-ion secondary batteries, and are manufactured by grinding them into particle sizes ranging from hundreds of nanometers to several micrometers using a jet mill to increase the packing density and calcination uniformity per unit volume.

[0008] Meanwhile, additive powder ground by a jet mill is used after undergoing weighing and packaging processes. Generally, hopper equipment is used for packaging the ground powder; the ground powder is discharged from the outlet of the hopper where it is stored, weighed using scales, and then packaged into packaging bags.

[0009] However, in the case of powders ranging in size from hundreds of nanometers to several micrometers, such as additives for cathode active materials of lithium-ion secondary batteries, rat hole phenomena, where the powder adheres to the hopper walls, and bridge phenomena, where the crushed powder aggregates around the hopper outlet and forms an arch structure that blocks the outlet, are prone to occur, making it difficult to accurately weigh and package a certain amount, and especially difficult to quickly weigh and package a large amount of crushed powder.

[0010] In addition, if impurities such as metal particles are introduced into the additive of the positive electrode active material of a lithium-ion secondary battery, they can not only damage the electrode structure due to friction and impact during the mixing process with the positive electrode active material, but also hinder the movement of lithium ions and react with the electrolyte during charging and discharging processes to induce gas generation or heat generation, which can lead to thermal runaway and easily result in safety issues; therefore, it is necessary to prevent magnetic materials such as metal particles from entering the additive of the positive electrode active material of a lithium-ion secondary battery.

[0011] Therefore, a solution to these problems is required when manufacturing additive powders for lithium-ion secondary battery cathode active materials. Prior art literature

[0012] 1. Republic of Korea Published Patent No. 10-2010-0086703 2. Republic of Korea Registered Patent No. 10-0708260 3. Republic of Korea Registered Patent No. 10-2579910 4. Republic of Korea Published Patent No. 10-2013-0003941 The problem to be solved

[0013] The present invention was created to solve the above-mentioned problems, and aims to provide a weighing device that can rapidly and accurately weigh and package a large amount of powder while preventing bridging or rat-hole phenomena caused by crushed powder in a hopper and preventing the inflow of magnetic foreign substances during the weighing and packaging of lithium-ion secondary battery cathode active material additive powder produced with particle sizes ranging from hundreds of nanometers to several micrometers. means of solving the problem

[0014] The present invention provides a weighing device for lithium-ion secondary battery electrode additive powder having a two-row screw comprising: a frame; a hopper installed on the upper part of the frame for feeding and storing crushed powder; two conveying sections installed to communicate with the lower part of the hopper and having a rotating screw installed inside that is rotatably installed across the hopper; a clamping section installed at one end of each of the conveying sections for fixing a packaging bag; and two weighing sections for measuring the weight of the packaging bag fixed to the clamping section.

[0015] In the present invention, the hopper includes a 'W'-shaped hopper body, and the conveying unit may be provided at the lower part of the hopper body.

[0016] In the present invention, the angle of inclination of the outer inclined surface of the hopper body may be 55 to 60°, and the angle of inclination of the inner inclined surface may be 40 to 50°.

[0017] In the present invention, the inner surface of the hopper body may include a Teflon coating layer with a thickness of 300 to 500 μm.

[0018] In the present invention, the frame includes an upper frame and a lower frame, a first load cell is disposed between the upper frame and the lower frame, and the hopper, conveying unit, and metering unit can be supported and fixed to the upper frame.

[0019] In the present invention, the metering unit may be connected and fixed to one end of the upper frame by a second load cell.

[0020] In the present invention, the rotary screw may include a tungsten coating layer with a thickness of at least 20 μm.

[0021] In the present invention, any one selected from boric acid (H3BO3), tungsten oxide (WO3), cobalt hydroxide (Co(OH)2), and yttrium oxide (Y2O3) may be used, but is not limited thereto. Effects of the invention

[0022] The lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw according to the present invention can prevent bridging or rat-hole phenomena caused by the powder from occurring in the hopper even under conditions where the lithium-ion secondary battery positive electrode active material additive is ground with a jet mill and then ground powder ranging in size from several hundred nanometers to several micrometers is fed into the hopper and operated for a long time.

[0023] In addition, it can prevent the inflow of magnetic foreign substances, such as metal particles caused by wear of the rotating screw during the discharge of the crushed powder, and can also accurately weigh and package the crushed powder at a high speed through two conveying and weighing sections, thereby increasing the work speed.

[0024] In addition, by accurately determining the remaining amount of crushed powder in the hopper, continuous weighing operations are possible, and the small installation space allows for increased space utilization in the weighing and packaging workspace. Brief explanation of the drawing

[0025] FIG. 1 is a perspective view showing the overall configuration of a lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw according to the present invention. Fig. 2 is a front view of Fig. 1. FIGS. 3 and FIGS. 4 are partial side cross-sectional views of the transfer section of FIG. 1. Fig. 5 is a plan view of Fig. 1. Specific details for implementing the invention

[0026] The embodiments of the present invention disclosed below are illustrative for the purpose of clarifying the features and effects of the present invention and methods for achieving them, and are not intended to be limited to specific embodiments; they should be understood to include all modifications, equivalents, or substitutions that fall within the technical spirit and scope of the present invention.

[0027] In the embodiments according to the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0028] The terms used in the embodiments according to the present invention are used merely to describe specific embodiments and are not intended to limit the embodiments according to the present invention, and singular expressions include plural expressions unless the context clearly indicates otherwise.

[0029] Unless otherwise defined in the embodiments of the present invention, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person with general knowledge in the art to which the present invention pertains.

[0030] Terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with the contextual meaning of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in the embodiments according to the present invention.

[0031] Hereinafter, specific technical details and embodiments of the lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw according to the present invention will be described in detail with reference to the attached drawings.

[0032] Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0033] Referring to FIGS. 1 to 5, the powder weighing device according to the present invention comprises a frame (100), a hopper (200) provided on the upper part of the frame (100) for receiving and storing lithium-ion secondary battery positive electrode active material additive powder that is crushed by a jet mill, then classified and dried, a conveying unit (300) installed in communication with the lower part of the hopper (200) for conveying the crushed powder, a clamp unit (400) provided at one end of the conveying unit (300) for fixing a packaging bag in which the discharged crushed powder is packaged, a weighing unit (500) for measuring the weight of the packaging bag, and a control unit (not shown) for controlling each of the above parts.

[0034] The above frame (100) includes an upper frame (110) that fixes and supports a hopper (200), a conveying unit (300), a clamping unit (400), and a weighing unit (500), a lower frame (120) provided at the bottom of the upper frame (110) and supporting the entire upper frame (110), and a first load cell (130) provided between the upper frame (110) and the lower frame (120).

[0035] The first load cell (130) can be positioned to measure the load of the entire upper frame (110), and in one embodiment, when the upper frame (110) and the lower frame (120) are cuboids, it can be positioned at the four vertices of the surface where the upper frame (110) and the lower frame (120) meet.

[0036] Therefore, since the weight of the hopper (200), conveying unit (300), clamping unit (400), and weighing unit (500) fixed and supported on the upper frame (110) can be measured in real time using the first load cell (130), the content of the crushed powder stored in the hopper (200) as well as the total weight of the crushed powder being discharged and weighed can be determined in real time, so the amount of crushed powder being weighed and packaged through the powder weighing device and the amount of crushed powder stored in the hopper (200) can be accurately determined.

[0037] If the amount of crushed powder inside the hopper body (220) is less than a certain amount, the control unit (not shown) can notify the operator of this using an alarm device or stop the operation of the powder weighing device.

[0038] In the present invention, the hopper (200) comprises an inlet (211) into which crushed powder crushed through a jet mill is fed and a cover (210) equipped with a dust collection filter (212), a hopper body (220) providing a space for storing and keeping the crushed powder, and an outlet (230) provided at the bottom of the hopper body (220).

[0039] The above hopper body (220) is configured in a 'W' shape when viewed from the front, and a total of four inclined surfaces (221) are formed. The angle of inclination (a2) of the outer inclined surface can be formed to be 55 to 60°, preferably 60°, and the angle of inclination (a1) of the inner inclined surface can be formed to be 40 to 50°, preferably 45°.

[0040] In addition, it is desirable to form a Teflon coating layer having a low coefficient of friction and excellent chemical resistance on the entire inner surface of the hopper (200) or the inner surface of the hopper body (220) to prevent adhesion with the crushed powder, thereby preventing the occurrence of rat holes and bridging phenomena and excluding the possibility of mixing with different types of crushed powder. The thickness of the Teflon coating layer is not limited, but a thickness of 300 to 500 μm is preferred.

[0041] Due to the above-mentioned inclination angle and / or Teflon coating, even if crushed powder accumulates inside the hopper body (200), rat hole or bridging phenomena do not occur, and it can be smoothly supplied to the discharge port (230).

[0042] In addition, two discharge ports (230) are formed at the bottom of the 'W'-shaped hopper body (220), allowing a large amount of crushed powder to be discharged simultaneously through the discharge ports, thereby enabling a large amount of crushed powder to be supplied to two conveying units (300) at a high speed. Furthermore, the discharge ports (230) are provided along the entire length (L) of the hopper body (220), which not only significantly reduces the bridging phenomenon that is prone to occur around the discharge ports (230), but also allows a larger amount of crushed powder to be supplied to the conveying units.

[0043] That is, the discharge port (230) may be configured in the form of a long slit formed along the longitudinal direction of the hopper body (220), for example, in the shape of a slit with a width of about 200 mm and a length of about 1,400 mm.

[0044] In the present invention, the conveying unit (300) is positioned at each of the two discharge ports (230) formed at the bottom of the hopper body (220) and is connected to the discharge ports (230) to serve the function of conveying crushed powder to a packaging bag. The conveying unit (300) includes a barrel (310) having a portion connected to the discharge ports (230) and a rotating screw (320) that conveys crushed powder while rotating inside the barrel (310).

[0045] A rotating screw (320), which is typically made of a metal material such as stainless steel, rotates at a rotational speed set by a control unit (not shown) and forcibly conveys the crushed powder, so it is prone to wear due to friction with the crushed powder, and the worn metal material may be mixed into the crushed powder. Therefore, in order to prevent wear and corrosion of the rotating screw (320), it is preferable that the rotating screw (320) be coated with tungsten (W) with a thickness of at least 20 μm, and it is preferable that the aspect ratio of the rotating screw (320) be 7 or higher.

[0046] In one embodiment, the rotating screw (320) may be made of SUS 304 with an outer diameter of about 160 mm and a length of about 1,490 mm, and a tungsten coating layer of about 30 μm formed on the surface.

[0047] In the present invention, the clamp part (400) is provided around the end of the conveying part (300), i.e., the discharge port (330), to support and fix a packaging bag (not shown) around the discharge port (330), so that the crushed powder conveyed through the conveying part (300) is fed into the packaging bag without scattering.

[0048] The clamp part (400) above is driven by an air cylinder with a pressure of about 4 bar and can stably secure the packaging bag.

[0049] In the present invention, the weighing unit (500) includes a support (510) that supports a packaging bag fixed to a clamp unit (400) and a second load cell (520) that is provided on one side of the support (510) and positioned on one side of the upper frame (110).

[0050] That is, since the support member (510) is supported and fixed to the upper frame (110) by the second load cell (520) (i.e., not in contact with the ground), the weight of the packaging bag (not shown) placed on the support member (510) can be measured in real time through the second load cell (520), so the weight of the crushed powder put into the packaging bag set through the control unit (not shown) can be accurately measured.

[0051] The operation process of the lithium-ion secondary battery electrode additive powder metering device according to the present invention is described below.

[0052] The crushed powder, crushed through the jet mill, is fed into the hopper body (220) through the inlet (211) in a classified or moisture-controlled state. After a certain amount of crushed powder is supplied, two packaging bags (not shown) are fixed around the discharge port (330) of the conveying unit (300) using two clamp parts (400), and then the weight of the crushed powder supplied to the packaging bags is set through the control unit (not shown), and then when the weighing switch (600), which is composed of a foot switch, etc., is operated, the rotating screw (320) rotates so that the crushed powder is conveyed and fed into the packaging bags (not shown).

[0053] The weight of the crushed powder fed into the packaging bag (not shown) supported by the support member (510) is measured by the second load cell (520), and when the crushed powder of a preset weight is fed into the packaging bag (not shown) through the control unit (not shown), the control unit (not shown) stops the operation of the rotating screw (320), and the packaging bag (not shown) is separated from the clamp unit (400) and transferred to the next packaging process.

[0054] As the weighing and packaging process is repeated, the weight of the crushed powder remaining in the hopper body (220) decreases, and the reduced weight of the crushed powder is measured in real time by the first load cell (130) provided in the frame (100). If the amount of crushed powder inside the hopper body (220) is less than a certain amount, the control unit (not shown) can notify the operator of this using an alarm device or stop the operation of the powder weighing device.

[0055] When transporting secondary battery positive electrode active material additives such as boric acid (H3BO3), tungsten oxide (WO3), cobalt hydroxide (Co(OH)2), and yttrium oxide (Y2O3) that have been ground by a jet mill using a conventional powder metering device, approximately 250 kg of ground powder can be processed per hour, whereas when using a two-row rotating screw (320) as in the lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw according to the present invention, approximately 1,000 kg of ground powder can be processed per hour, thus confirming that the processing capacity of the ground powder is improved by approximately 400%.

[0056] In addition, when weighing and packaging 1 ton of crushed powder using a 5kg aluminum packaging bag with a conventional weighing device, it takes about 4 hours, but in the case of the lithium-ion secondary battery electrode additive powder weighing device equipped with a 2-row screw according to the present invention, the working time is reduced to about 1 hour.

[0057] The lithium-ion secondary battery electrode additive powder weighing device equipped with a two-row screw according to the present invention can prevent bridging or rat-hole phenomena caused by the secondary battery positive electrode active material additive powder through the effects of an inclination angle formed on the hopper body and a Teflon coating, and can significantly increase the content of crushed powder weighed and packaged per hour by using a two-row rotating screw. Furthermore, it can measure the content of crushed powder packaged in the packaging bag and the content of crushed powder stored in the hopper in real time, thereby providing the advantage of simultaneously ensuring accuracy and continuity of weighing and packaging operations, and can prevent magnetic foreign substances such as metal materials from being mixed into the lithium-ion secondary battery electrode additive powder.

[0058] The following describes additional configurations of a lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw according to the present invention.

[0059] The lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw according to the present invention may further include an air vibrator (240) for applying vibration to the hopper body (210), and six air vibrators may be installed throughout the entire 'W'-shaped hopper body (210).

[0060] The lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw according to the present invention may further include an air fluidizer (250) that blows air into the interior of the hopper body (210), and four air fluidizers may be installed throughout the entire 'W'-shaped hopper body (210).

[0061] As described above, the present invention has been explained with reference to an embodiment illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent embodiments are possible therefrom. Explanation of the symbols

[0062] 100; Frame, 110; Upper frame, 120; Lower frame, 130; First load cell 200; Hopper, 210; Cover, 220; Hopper body, 221; Inclined surface, 230; Discharge port 300; conveying section, 310; barrel, 320; rotary screw 400; clamp part 500; metering unit, 510; support, 520; second load cell 600; metering switch

Claims

Claim 1 A lithium-ion secondary battery electrode additive powder weighing device having a two-row screw, comprising: a frame; a hopper installed on the upper part of the frame for feeding and storing crushed powder; two conveying sections installed to communicate with the lower part of the hopper and having a rotating screw installed inside that is rotatably installed across the hopper; and two weighing sections installed at one end of each of the conveying sections for fixing a packaging bag and measuring the weight of the packaging bag fixed to the clamping section; wherein the frame comprises an upper frame and a lower frame, a first load cell is disposed between the upper frame and the lower frame, and the hopper, conveying section, and weighing section are supported and fixed to the upper frame. Claim 2 A lithium-ion secondary battery electrode additive powder weighing device having two rows of screws, characterized in that, in claim 1, the hopper comprises a 'W'-shaped hopper body, and the conveying unit is respectively provided at the lower part of the hopper body. Claim 3 A lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw, characterized in that, in paragraph 2, the angle of inclination of the outer inclined surface of the hopper body is 55 to 60° and the angle of inclination of the inner inclined surface is 40 to 50°. Claim 4 A lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw, characterized in that, in paragraph 2, the interior of the hopper body is coated with a Teflon coating having a thickness of 300 to 500 μm. Claim 5 delete Claim 6 A lithium-ion secondary battery electrode additive powder weighing device having a two-row screw, wherein, in claim 1, the weighing unit is connected and fixed to one end of the upper frame by a second load cell. Claim 7 A lithium-ion secondary battery electrode additive powder metering device having a two-row screw, wherein the rotary screw is coated with tungsten with a thickness of at least 20 μm in the first aspect. Claim 8 A lithium-ion secondary battery electrode additive powder metering device equipped with a two-row screw, characterized in that, in claim 1, the ground powder is one selected from boric acid, tungsten oxide, cobalt hydroxide, and yttrium oxide.

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