Method and device for controlling electrode slurry supply rate

Abstract

A method for controlling the supply amount of slurry for electrodes according to the present invention includes the steps of: supplying slurry from a first tank to a coater; when the amount of the slurry stored in the first tank decreases and the level of the first tank reaches a first predetermined level, supplying the slurry from a second tank connected to the first tank to the first tank for a predetermined time; and automatically interrupting the supply of the slurry from the second tank to the first tank after the predetermined time has elapsed.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0134890, filed October 19, 2022, and Korean Patent Application No. 10-2023-0134390, filed October 10, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a method and apparatus for controlling the supply amount of electrode slurry, and more particularly to a method and apparatus for controlling the supply amount of electrode slurry supplied between tanks in order to prevent oversupply of electrode slurry and minimize temperature changes in the supplied electrode slurry. [Background technology]

[0003] Secondary batteries, which can be repeatedly charged and discharged, are used in a variety of electronic devices. Meanwhile, as the types and shapes of electronic devices become more diverse, the shapes of secondary batteries installed in electronic devices also become more diverse. Recently, lithium-ion secondary batteries, which use lithium, have become widely used as secondary batteries.

[0004] To manufacture such a secondary battery, a negative electrode coated with a negative electrode active material, a positive electrode coated with a positive electrode active material, and a separator disposed between the negative and positive electrodes are required. To manufacture such negative and positive electrode active materials, a mixture of electrode active material, conductive material, binder, etc., called a slurry, is often required.

[0005] Specifically, the manufacturing of positive and negative electrodes involves a mixing process, in which raw materials are mixed, followed by coating, drying, roll pressing, taping, slitting, and other processes. During the mixing process, raw materials such as electrode active material, conductive material, and binder are mixed to create a uniform slurry. Heat from mixing gradually rises during the mixing process, so the subsequent transportation process involves adjusting the slurry temperature to the desired level using cooling water through various tanks. The slurry formed in the mixer is transported through storage tanks, transfer tanks, and finally to a supply tank, where it is supplied to the coating roll.

[0006] Since the slurry temperature affects coating quality and loading deviation during the coating process, controlling it at an appropriate level is crucial for ensuring consistent electrode quality. To control the slurry temperature, an impeller is typically rotated inside the tank and cooling water is supplied to the tank walls to transfer heat to the outside. The temperature of the cooling water is adjusted to match the slurry temperature to the target temperature, and a temperature control method using proportional integral derivative control (PID control) or a proportional control method using the difference between the target temperature and the current temperature can be used.

[0007] Although electrode coating is performed continuously, the slurry is mixed in batches, resulting in a temperature profile of the transferred slurry that periodically fluctuates. In sections where the temperature changes rapidly, proportional temperature control can result in excessively long times for the slurry to stabilize at the target temperature. This can affect product yields with desired physical properties and can lead to reduced production volume due to process interruptions to stabilize the slurry temperature.

[0008] Referring to FIG. 6, according to the prior art, in order to maintain a target level (e.g., 41%) for slurry storage in a supply tank, the supply of slurry is initiated at a level lower than the target level (e.g., 40%), and then stopped from the transfer tank when the target level (e.g., 41%) is reached again. However, due to the length of the piping between the supply tank and the transfer tank, stopping the supply of slurry at the target level results in an oversupply of slurry below the desired target level. Furthermore, if the supply of slurry is initiated from the transfer tank at a level lower than the target level (e.g., 40%), the supply tank continues to supply slurry to the coating roll while the transfer tank is transferring the slurry, due to the length of the piping between the supply tank and the transfer tank, causing the level in the supply tank to further drop. This results in a large disturbance, as in the comparative example shown in FIG. 5.

[0009] Therefore, there is a need for more efficient automatic control of the amount of slurry supplied between such tanks in order to prevent oversupply of slurry and to stabilize the temperature of the slurry. Summary of the Invention [Problem to be solved by the invention]

[0010] The problem to be solved by the present invention is to improve the conventional electrode slurry supply method to prevent oversupply of slurry and minimize temperature changes of the slurry, thereby improving manufacturing efficiency and product quality.

[0011] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0012] A method for controlling a supply amount of electrode slurry according to one embodiment of the present invention may include the steps of: supplying the slurry from a first tank to a coater; when the amount of the slurry stored in the first tank decreases and the level of the first tank reaches a first predetermined level, supplying the slurry from a second tank connected to the first tank to the first tank for a predetermined time; and automatically interrupting the supply of the slurry from the second tank to the first tank after the predetermined time has elapsed.

[0013] The method may further include again supplying the slurry from the second tank to the first tank for the predetermined time period when the level in the first tank again reaches the first predetermined level.

[0014] The first predetermined level may be a target level for storage of the slurry in the first tank.

[0015] The method may further include a step of interrupting the supply of the slurry from the second tank to the first tank when the level of the first tank reaches a second predetermined level while the slurry is being supplied from the second tank to the first tank for the predetermined time, and the second predetermined level may be lower than an upper limit level of the storage amount of the slurry in the first tank.

[0016] The level of the first tank may be the height or volume of the first tank.

[0017] The first tank may have a capacity for receiving the slurry smaller than the capacity for receiving the slurry of the second tank.

[0018] According to another embodiment of the present invention, a method for controlling the supply amount of electrode slurry may further include a step of measuring the temperature of the first tank and a step of measuring the temperature of the second tank, and may include a step of controlling the supply amount of the slurry from the second tank to the first tank based on the temperature of the first tank and the temperature of the second tank.

[0019] The step of controlling the amount of slurry supplied from the second tank to the first tank may include a step of increasing the amount of slurry supplied from the second tank to the first tank when the temperature of the first tank falls within a predetermined normal temperature range and the temperature of the second tank falls within the predetermined normal temperature range.

[0020] The step of controlling the supply rate of the slurry from the second tank to the first tank may include a step of maintaining the supply rate of the slurry from the second tank to the first tank when the temperature of the first tank falls within a predetermined normal temperature range and the temperature of the second tank is higher or lower than the predetermined normal temperature range.

[0021] The step of controlling the amount of slurry supplied from the second tank to the first tank may include a step of increasing the amount of slurry supplied from the second tank to the first tank when the temperature of the first tank is higher or lower than a predetermined normal temperature range and the temperature of the second tank falls within the predetermined normal temperature range.

[0022] The step of controlling the amount of slurry supplied from the second tank to the first tank may include the step of increasing the amount of slurry supplied from the second tank to the first tank when the temperature of the first tank is higher than a predetermined normal temperature range and the temperature of the second tank is lower than the predetermined normal temperature range.

[0023] The step of controlling the amount of slurry supplied from the second tank to the first tank may include the step of increasing the amount of slurry supplied from the second tank to the first tank when the temperature of the first tank is lower than a predetermined normal temperature range and the temperature of the second tank is higher than the predetermined normal temperature range.

[0024] The step of controlling the amount of slurry supplied from the second tank to the first tank may include a step of maintaining the amount of slurry supplied from the second tank to the first tank when the temperature of the first tank is higher than a predetermined normal temperature range and the temperature of the second tank is higher than the predetermined normal temperature range.

[0025] The step of controlling the amount of slurry supplied from the second tank to the first tank may include a step of maintaining the amount of slurry supplied from the second tank to the first tank when the temperature of the first tank is lower than a predetermined normal temperature range and the temperature of the second tank is lower than the predetermined normal temperature range.

[0026] The predetermined normal temperature range may be a temperature range that is preset to be suitable for coating the slurry.

[0027] An electrode slurry supply device that performs the method for controlling the supply amount of electrode slurry according to one embodiment of the present invention may include a coater that coats the slurry, a first tank that supplies the slurry to the coater, a second tank that stores the slurry and supplies it to the first tank, piping that connects the first tank and the second tank, and a valve provided in the piping. [Effects of the Invention]

[0028] According to the present invention, the amount of slurry supplied between the tanks can be automatically controlled, effectively preventing oversupply of slurry. Furthermore, by adjusting the amount of slurry supplied between the tanks in real time according to the temperature of each tank, it is possible to minimize changes in the temperature of the slurry, stabilize the temperature of the slurry, and maximize production efficiency of the electrode assembly.

[0029] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief explanation of the drawings]

[0030] [Figure 1] 3 is a cross-sectional view schematically showing a movement path of a slurry in an electrode manufacturing process. FIG. [Figure 2] 10 is a diagram illustrating a process of discharging an electrode slurry through an electrode slurry slot die onto an electrode current collector placed on a coating roller. FIG. [Figure 3] 3 is a flowchart showing a method for controlling the supply amount of electrode slurry according to one embodiment of the present invention. [Figure 4] 10 is a schematic diagram illustrating an algorithm for controlling the supply amount of electrode slurry according to a temperature according to another embodiment of the present invention. [Figure 5] 7 shows comparative experimental data results of the level change of the supply tank according to the embodiment of FIG. 3 and the level change of the supply tank according to the prior art of FIG. 6. [Figure 6] 3 shows the level change of a supply tank according to the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may be embodied in various different forms and is not limited to the embodiments set forth herein.

[0032] In order to clearly describe the present invention, parts not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0033] Furthermore, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown. Thicknesses are exaggerated in the drawings to clearly show various layers and regions. Also, in the drawings, the thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0034] Furthermore, when a layer, film, region, plate, or other part is said to be "on" or "above" another part, this includes not only the case where it is "directly above" that part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Furthermore, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" in the opposite direction of gravity.

[0035] Furthermore, throughout the specification, when a part is said to "comprise" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0036] Also, throughout the specification, when we say "on a plane," it means when the subject part is viewed from above, and when we say "on a cross section," it means when the subject part is cut vertically and viewed from the side.

[0037] Fig. 1 is a cross-sectional view schematically showing the path of slurry movement in an electrode manufacturing process. Fig. 2 shows an electrode slurry coater 600 connected to the supply tank 500 of Fig. 1. The apparatuses of Fig. 1 and 2 are used to implement the method of controlling the supply amount of electrode slurry of the present invention.

[0038] Referring to FIG. 1, an electrode active material, a conductive material, a binder, and the like are mixed in a mixer 100 to produce a slurry. That is, the slurry is a slurry for manufacturing an electrode and may contain an electrode active material. The slurry may be transferred sequentially to a storage tank 200, a buffer tank 300, a transfer tank 400, and a supply tank 500. Transfer piping may be installed between each tank to allow the slurry to move.

[0039] The storage tank 200 is a tank into which the slurry mixed in the mixer 100 is discharged and temporarily stored. The buffer tank 300 and the transfer tank 400 are tanks installed between the storage tank 200 and the supply tank 500 to continuously supply the slurry produced in one unit to the supply tank 500. The supply tank 500 is a tank for supplying the slurry to the coater 600. The storage tank 200 and / or the buffer tank 300 may be selectively omitted depending on the environment in which the present invention is embodied.

[0040] Although not specifically shown in Fig. 1, each of the tanks 200, 300, 400, and 500 further includes a temperature sensor (not shown). A control valve (not shown) that receives the temperature value of the electrode slurry measured by the temperature sensor and controls the flow rate of the electrode slurry is provided in the piping between each of the tanks 200, 300, 400, and 500. Each control valve receives the temperature value of the electrode slurry measured by the temperature sensor and controls the flow rate from the previous tank to the subsequent tank for each section. In addition, the piping between each of the tanks 200, 300, 400, and 500 further includes a pump (not shown) that pumps the electrode slurry from the previous tank to the subsequent tank.

[0041] The slurry receiving capacity of the supply tank 500 may be smaller than the slurry receiving capacity of the transfer tank 400. When the slurry receiving capacity of the supply tank 500 is, for example, 500 L, 200 L, or 120 L, the slurry receiving capacity of the transfer tank 400 may be, for example, 800 L. The present invention is not limited to the above, and the capacities of the supply tank 500 and the transfer tank 400 may be variously modified and changed depending on the environment in which the present invention is embodied.

[0042] 2 shows an electrode slurry coater 600 connected to the supply tank 500 of FIG. 1. The electrode slurry coater 600 includes an electrode slurry slot die 610 that discharges the electrode slurry supplied from the supply tank 500 and a coating roll 620 that supports and transports the current collector layer 700. The electrode slurry coater 600 also includes a temperature sensor (not shown) that measures the temperature of the electrode slurry discharged from the electrode slurry slot die 610. The current collector layer 700 is transported along the coating roll 620, and the electrode slurry discharged from the electrode slurry slot die 610 is coated onto one or both sides of the current collector layer 700. After the electrode slurry is coated onto the current collector layer 700, processes such as drying and roll pressing may be performed.

[0043] FIG. 3 is a flowchart showing a method for controlling the supply rate of electrode slurry according to one embodiment of the present invention.

[0044] Slurry is supplied from the supply tank 500 to the coater 600 (S100). At this time, as the slurry is supplied from the supply tank 500 to the coater 600, the amount of slurry stored in the supply tank 500 gradually decreases. The amount of slurry stored in the supply tank 500 is expressed as a level (percentage) based on the total volume or height of the supply tank 500 being 100.

[0045] It is determined whether the amount of slurry stored in the supply tank 500 decreases and the level of the supply tank 500 reaches a first predetermined level (S200). When the amount of slurry stored in the supply tank 500 decreases and the level of the supply tank 500 reaches the first predetermined level, the transfer tank 400 connected to the supply tank 500 supplies the slurry to the supply tank 500 for a predetermined time (S300). The time for supplying the slurry from the transfer tank 400 to the supply tank 500 is a time that is preset according to the environment in which the present invention is embodied. For example, it may be 3 seconds. However, the present invention is not limited thereto, and the time for supplying the slurry from the transfer tank 400 to the supply tank 500 may be selected and set in advance depending on the type of electrode slurry, the capacity of the transfer tank 400 and / or the supply tank 500, the length of the piping connecting the transfer tank 400 and the supply tank 500, etc.

[0046] The first predetermined level of the supply tank 500 is a level at which supply from the transfer tank 400 to the supply tank 500 begins. The first predetermined level is a level preset by an operator in the process, and may be a target level of the amount of slurry stored in the supply tank 500. That is, it may be a level at which an appropriate amount is stored in the supply tank 500 in the process, and may be predetermined by modifying or changing it depending on the environment in which the present invention is embodied.

[0047] The first predetermined level is selected between an upper limit and a lower limit of the storage amount of the slurry in the supply tank 500. The lower limit of the storage amount of the slurry in the supply tank 500 refers to a lower limit line set to prevent a situation in which the storage amount in the supply tank 500 becomes low and a process interruption occurs when supplying electrode slurry from the supply tank 500 to the coater 600, necessitating the need to receive additional supply of slurry from the transfer tank 400. Similarly, there is also an upper limit of the storage amount of the slurry in the supply tank 500, which refers to an upper limit line set to prevent oversupply of slurry to the supply tank 500. The lower limit and upper limit levels may also be levels set in advance by an operator according to the capacity and conditions of the supply tank 500 in the process.

[0048] Meanwhile, when the amount of slurry stored in the supply tank 500 is below the target level and the valve between the supply tank 500 and the transfer tank 400 is turned on and opened to adjust the amount of slurry stored in the supply tank 500 to the target level, the slurry is not immediately supplied to the supply tank 500 because it takes time for the slurry to move due to the length of the piping between the supply tank 500 and the transfer tank 400. Therefore, the first predetermined level of the supply tank 500 at which the valve between the supply tank 500 and the transfer tank 400 is turned on and opened may be the target level of the amount of slurry stored in the supply tank 500. However, the present invention is not necessarily limited thereto, and the operator may preset the first predetermined level according to the environment in which the present invention is applied.

[0049] The important point is that when the amount of slurry stored in the supply tank 500 reaches a first predetermined level, the process of turning on and opening the valve between the supply tank 500 and the transfer tank 400 to supply the slurry from the transfer tank 400 to the supply tank 500 is performed for the predetermined time as described above. After the predetermined time has elapsed, the supply of the slurry from the transfer tank 400 to the supply tank 500 is automatically stopped (S400).

[0050] Therefore, even if the valve between the supply tank 500 and the transfer tank 400 is turned off and closed, it takes time for the slurry to move to the supply tank 500 due to the length of the piping between the supply tank 500 and the transfer tank 400, so it is possible to prevent the problem of slurry continuing to be added to the supply tank 500 that has already reached its upper limit level.

[0051] Therefore, when the predetermined time has elapsed, the supply of slurry from the transfer tank 400 to the supply tank 500 is automatically interrupted, thereby preventing the possibility of a disturbance occurring if slurry continues to be added to the supply tank 500. When the level of the supply tank 500 again reaches the first predetermined level as described above, the step (S300) of supplying slurry from the transfer tank 400 to the supply tank 500 for a predetermined time is repeated. Similarly, when the predetermined time has elapsed, the supply of slurry from the transfer tank 400 to the supply tank 500 is automatically interrupted (S400).

[0052] Of course, the method may further include a step of interrupting the supply of slurry from the transfer tank 400 to the supply tank 500 when the level of the supply tank 500 reaches a second predetermined level even if a predetermined time has not elapsed when the slurry is supplied from the transfer tank 400 to the supply tank 500 (S300). The second predetermined level may be preset to a value higher than the first predetermined level and lower than the upper limit level of the storage amount of the slurry in the supply tank 500.

[0053] 4 is a schematic diagram of an algorithm for controlling the supply amount of electrode slurry according to another embodiment of the present invention based on temperature. More specifically, this algorithm controls the amount of slurry supplied from the transfer tank 400 to the supply tank 500 based on the temperatures of the transfer tank 400 and the supply tank 500. When the temperature difference between the transfer tank 400 and the supply tank 500 is large, the level in the supply tank 500 is lowered to make the temperature more likely to change, or a minimum supply is provided to reduce disturbances. When the temperature difference is small, the algorithm gradually increases the amount of slurry supplied to the supply tank 500 (i.e., increases the volume of slurry at the same temperature) to reduce the impact on future disturbances.

[0054] First, the method for controlling the supply amount of electrode slurry according to the present invention further includes the steps of measuring the temperature of the supply tank 500 and the transfer tank 400 .

[0055] In addition, the step (S300) of supplying the slurry from the transfer tank 400 to the supply tank 500 for a predetermined time includes a step of controlling the amount of slurry supplied from the transfer tank 400 to the supply tank 500 depending on the temperature of the supply tank 500 and the temperature of the transfer tank 400. At this time, in step S300, it is determined whether the temperature of the supply tank 500 and the temperature of the transfer tank 400 each fall within a predetermined normal temperature range.

[0056] Here, the predetermined normal temperature range refers to a target temperature range preset by an operator in an electrode manufacturing process. For example, it refers to a temperature range desired by an operator, such that when the temperature of the slurry falls within the normal temperature range (target temperature range), the quality of the electrode can be maintained constant and the defect rate can be reduced. The predetermined normal temperature range may be predetermined and modified depending on the environment in which the present invention is embodied.

[0057] At this time, the specific algorithm for controlling the supply amount of the slurry from the transfer tank 400 to the supply tank 500 is as follows.

[0058] 1-1. When the temperature of the supply tank 500 falls within a predetermined normal temperature range and the temperature of the transfer tank 400 falls within a predetermined normal temperature range, the amount of slurry supplied from the transfer tank 400 to the supply tank 500 is increased.

[0059] In other words, when the temperature of the supply tank 500 and the temperature of the transfer tank 400 are both within the normal temperature range, the amount of slurry supplied from the transfer tank 400 to the supply tank 500 is increased so that the supply tank 500 directly connected to the coater 600 can hold more normal-state slurry.

[0060] 1-2. When the temperature of the supply tank 500 is within a predetermined normal temperature range and the temperature of the transfer tank 400 is higher or lower than the predetermined normal temperature range, the amount of slurry supplied from the transfer tank 400 to the supply tank 500 is maintained. In other words, if more slurry of an abnormal temperature than necessary is supplied to the supply tank 500, the disturbance caused by the temperature change of the slurry will increase, so the supply amount is maintained at a minimum amount sufficient to maintain the amount of slurry consumed in the supply tank 500.

[0061] In this case, if the temperature of the transfer tank 400 is not within the normal temperature range and the slurry is not supplied from the transfer tank 400 to the supply tank 500, problems may occur during the process of supplying the slurry from the supply tank 500 to the coater 600 to coat the electrode slurry. Furthermore, according to the present invention, the slurry is not supplied endlessly from the transfer tank 400 to the supply tank 500 but is supplied only for a predetermined period of time as described above. Therefore, the slurry supplied from the transfer tank 400 to the supply tank 500 is combined with the slurry already stored in the supply tank 500, and the temperature change in the supply tank 500 may not be so great relatively.

[0062] 2-1. When the temperature of the supply tank 500 is higher or lower than the predetermined normal temperature range and the temperature of the transfer tank 400 falls within the predetermined normal temperature range, the amount of slurry supplied from the transfer tank 400 to the supply tank 500 is increased. In other words, even if the temperature of the supply tank 500 falls within the abnormal temperature range, the temperature of the slurry in the supply tank 500 can be relatively changed toward the normal temperature range by increasing the amount of slurry supplied from the transfer tank 400 that falls within the normal temperature range.

[0063] 2-2.(a) When the temperature of the supply tank 500 is higher than a predetermined normal temperature range and the temperature of the transfer tank 400 is lower than a predetermined normal temperature range, the amount of slurry supplied from the transfer tank 400 to the supply tank 500 is increased. In other words, the temperature of the slurry already stored in the supply tank 500 and the temperature of the slurry supplied from the transfer tank 400 cancel each other out to achieve an equilibrium state, thereby stabilizing the temperature of the slurry in the supply tank 500.

[0064] 2-2.(b) When the temperature of the supply tank 500 is lower than the predetermined normal temperature range and the temperature of the transfer tank 400 is higher than the predetermined normal temperature range, the amount of slurry supplied from the transfer tank 400 to the supply tank 500 is increased. In other words, the temperature of the slurry already stored in the supply tank 500 and the temperature of the slurry supplied from the transfer tank 400 cancel each other out to achieve an equilibrium state, thereby stabilizing the temperature of the slurry in the supply tank 500.

[0065] 2-3.(a) When the temperature of the supply tank 500 is higher than the predetermined normal temperature range and the temperature of the transfer tank 400 is higher than the predetermined normal temperature range, the amount of slurry supplied from the transfer tank 400 to the supply tank 500 is maintained. In other words, if more slurry of an abnormal temperature is supplied to the supply tank 500 than necessary, the disturbance caused by the temperature change of the slurry will become greater, so the supply amount is maintained at a minimum amount sufficient to maintain the amount of slurry consumed in the supply tank 500.

[0066] 2-3.(b) When the temperature of the supply tank 500 is lower than the predetermined normal temperature range and the temperature of the transfer tank 400 is lower than the predetermined normal temperature range, the amount of slurry supplied from the transfer tank 400 to the supply tank 500 is maintained. In other words, if more slurry at an abnormal temperature than necessary is supplied to the supply tank 500, the disturbance caused by the temperature change of the slurry will become greater, so the supply amount is maintained at a minimum amount sufficient to maintain the amount of slurry consumed in the supply tank 500.

[0067] In cases 2-3(a) and (b), similar to the case 1-2, if the temperature of the transfer tank 400 is not within the normal temperature range and slurry is not supplied from the transfer tank 400 to the supply tank 500, problems may occur during the process of supplying the slurry from the supply tank 500 to the coater 600 to coat the electrode slurry. Therefore, the supply amount is maintained at a minimum amount sufficient to maintain the amount of slurry consumed in the supply tank 500.

[0068] The predetermined normal temperature range is a temperature range that is preset to be suitable for coating a slurry, and may be preset in various ways depending on the environment in which the present invention is implemented, the type of slurry, and the like.

[0069] In one embodiment, the predetermined normal temperature range may be set within a range of, for example, 23° C. to 33° C. Alternatively, the predetermined normal temperature range may be set within a range of 23° C. to 26° C., for example, 23° C.

[0070] The electrode to be manufactured in the present invention is an electrode for a secondary battery. The electrode slurry is a general term for a slurry composition containing an electrode active material. The positive electrode or negative electrode refers to an electrode for a secondary battery, specifically, an electrode for a lithium secondary battery.

[0071] In one embodiment, the electrode refers to the positive electrode and / or negative electrode of a lithium secondary battery.

[0072] The positive electrode has a structure in which a two-layer positive electrode active material layer is laminated on a positive electrode current collector. In one example, the positive electrode active material layer includes a positive electrode active material, a conductive material, a binder polymer, etc., and may further include a positive electrode additive commonly used in the art, if necessary.

[0073] The positive electrode active material may be a lithium-containing oxide, which may be the same or different. As the lithium-containing oxide, a lithium-containing transition metal oxide may be used.

[0074] For example, the lithium-containing transition metal oxide is Li , x , 2-z , z , x , , x , z , x , 2-z ,

[0075] CoO2 (0.5 < x < 1.3), Li x NiO2 (0.5 < x < 1.3), Li x MnO2 (0.5 < x < 1.3), Li x Mn2O4 (0.5 < x < 1.3), Li x (Ni a Co b Mn c )O2 (0.5 < x < 1.3, 0 < a < 1, 0 < b < 1, 0 < c < 1, a + b + c = 1), Li x Ni 1-y Co y [[ID=...]]O2 (0.5 < x < 1.3, 0 < y < 1), Li x Co 1-y Mn y O2 (0.5 < x < 1.3, 0 ≤ y < 1), Li x Ni 1-y Mn y O2 (0.5 < x < 1.3, O ≤ y < 1), Li x (Ni a Co b Mn c )O4 (0.5 < x < 1.3, 0 < a < 2, 0 < b < 2, 0 < c < 2, a + b + c = 2), Li x Mn 2-z Ni z O4 (0.5 < x < 1.3, 0 < z < 2), Li x Mn 2-z Co z O4 (0.5 < x < 1.3, 0 < z < 2), Li x CoPO4 (0.5 < x < 1.3) and Li x FePO4 (0.5 < x < 1.3), and may be a mixture of one or more selected from the group consisting of two or more of these. The lithium-containing transition metal oxide may be coated with a metal or metal oxide such as aluminum (Al). Further, in addition to the lithium-containing transition metal oxide, one or more selected from the group consisting of sulfides, selenides, and halides may also be used.

[0075] It should be noted that there are some ellipses (...) in the translation to indicate that parts of the original text tags are repeated in a pattern that is difficult to fully write out in the same format while maintaining readability. The overall meaning and structure of the text are translated as accurately as possible according to the rules.The positive electrode active material may be contained in the positive electrode active material layer in a range of 94.0 to 98.5 wt %. When the content of the positive electrode active material satisfies this range, it is advantageous in terms of fabricating a high-capacity battery, providing sufficient positive electrode conductivity, and providing adhesive strength between electrode materials.

[0076] The current collector used for the positive electrode may be any metal that is highly conductive, easily adheres to the positive electrode active material slurry, and is non-reactive within the voltage range of the electrochemical device. Specific examples of the current collector for the positive electrode include foils made of aluminum, nickel, or a combination thereof.

[0077] The positive electrode active material layer further contains a conductive material. The conductive material is typically added in an amount of 1 to 30 wt % based on the total weight of the mixture containing the positive electrode active material. There are no particular limitations on the conductive material, as long as it is conductive and does not induce chemical changes in the secondary battery. For example, the conductive material may be one or more selected from the group consisting of graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives.

[0078] The negative electrode has a structure in which a two-layer negative electrode active material layer is laminated on a negative electrode current collector. In one example, the negative electrode active material layer includes a negative electrode active material, a conductive material, a binder polymer, etc., and may further include a negative electrode additive commonly used in the art, as needed.

[0079] The negative electrode active material may include a carbon material, lithium metal, silicon, or tin. When a carbon material is used as the negative electrode active material, both low-crystalline carbon and high-crystalline carbon may be used. Typical low-crystalline carbons include soft carbon and hard carbon, while typical high-crystalline carbons include one or more high-temperature-calcined carbons selected from the group consisting of natural graphite, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, carbon microbeads, mesophase pitches, and petroleum or coal tar pitch-derived cokes.

[0080] Non-limiting examples of the current collector used in the negative electrode include foils made of copper, gold, nickel, copper alloys, or combinations thereof. The current collector may also be formed by laminating a substrate made of any of the above materials.

[0081] The negative electrode may also contain a conductive material and a binder commonly used in the art.

[0082] FIG. 5 shows the results of comparative experimental data of the level change of the supply tank according to the embodiment (Example 1) of FIG. 3 and the level change of the supply tank according to the prior art of FIG.

[0083] In the graph of FIG. 5, the solid line is a graph showing the level change of the supply tank 500 according to the first embodiment of the present invention, and the dashed line is a graph showing the level change of the supply tank 500 according to the prior art as a comparative example.

[0084] In both Example 1 and Comparative Example, the experiments were carried out in the case where the storage capacity of transfer tank 400 was about 800 L and the storage capacity of supply tank 500 was about 120 L in the case of positive electrode slurry.

[0085] Example 1 of the present invention corresponds to the case where slurry is supplied from transfer tank 400 to supply tank 500 for a predetermined period of 3 seconds, and then stopped and this process is repeated, as described above with reference to Fig. 3. The comparative example corresponds to the case described as the prior art in the Background Art section.

[0086] 5, when the stable target level of the supply tank 500 is 41%, in Example 1 of the present invention, the level of the supply tank 500 is maintained at a constant level within a range of 40% to 41% (i.e., within a 1% range) without significant fluctuations, allowing for a stable electrode coating process, whereas in the comparative example, the level of the supply tank 500 is within a range of 38% to 54% (i.e., within a 16% range), fluctuating more significantly than in Example 1. As a result, the temperature (disturbance) change according to the level of the supply tank 500 is approximately 0.2°C in the comparative example, while it is approximately 0.01°C in Example 1, resulting in a significant improvement in stability.

[0087] As described above, according to the method for controlling the supply amount of electrode slurry according to an embodiment of the present invention, the conventional method for supplying electrode slurry is improved by supplying the slurry for a predetermined time when a preset level is reached and then pausing the supply, and then repeating the process of supplying the slurry for a predetermined time when the preset level is reached again and pausing the supply, thereby preventing oversupply of slurry and minimizing the temperature change of the slurry that occurs as a result.

[0088] Furthermore, by adjusting the amount of slurry supplied from the transfer tank to the supply tank in real time according to the respective temperatures of the supply tank and the transfer tank, it is possible to minimize temperature changes in the supply tank slurry connected to the electrode coater and stabilize the temperature of the slurry.

[0089] Due to the above advantages, the production efficiency of the electrode assembly can be maximized, and the manufacturing efficiency and product quality can be improved.

[0090] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0091] 100: Mixer 200: Storage tank 300: Buffer tank 400: Transfer tank 500: Supply tank 600: Coater 700: Current collector layer

Claims

1. A method for controlling a supply amount of electrode slurry, comprising: supplying the slurry from the first tank to a coater; When the amount of the slurry stored in the first tank decreases and the level of the first tank reaches a first predetermined level, supplying the slurry from a second tank connected to the first tank to the first tank for a predetermined time; and automatically interrupting the supply of the slurry from the second tank to the first tank after the predetermined time has elapsed.

2. 2. The method for controlling the supply amount of electrode slurry according to claim 1, further comprising the step of again supplying the slurry from the second tank to the first tank for the predetermined time when the level of the first tank reaches the first predetermined level again.

3. 2. The method for controlling a supply amount of electrode slurry according to claim 1, wherein the first predetermined level is a target level of the amount of the slurry stored in the first tank.

4. the method further comprising the step of interrupting the supply of the slurry from the second tank to the first tank when the level of the first tank reaches a second predetermined level while the slurry is being supplied from the second tank to the first tank for the predetermined time; 2. The method for controlling a supply amount of electrode slurry according to claim 1, wherein the second predetermined level is higher than the first predetermined level and lower than an upper limit level of the storage amount of the slurry in the first tank.

5. 2. The method for controlling a supply amount of electrode slurry according to claim 1, wherein the level of the first tank is a height or a volume of the first tank.

6. 2. The method for controlling a supply amount of slurry for an electrode according to claim 1, wherein a capacity of the first tank for receiving the slurry is smaller than a capacity of the second tank for receiving the slurry.

7. A method for controlling a supply amount of electrode slurry, comprising: measuring the temperature of the first tank; measuring the temperature of the second tank; and controlling the amount of slurry supplied from the second tank to the first tank based on the temperature of the first tank and the temperature of the second tank.

8. 8. The method for controlling a supply amount of slurry for an electrode according to claim 7, wherein the step of controlling the supply amount of the slurry from the second tank to the first tank includes the step of increasing the supply amount of the slurry from the second tank to the first tank when the temperature of the first tank falls within a predetermined normal temperature range and the temperature of the second tank also falls within the predetermined normal temperature range.

9. 8. The method for controlling a supply rate of slurry for an electrode according to claim 7, wherein the step of controlling the supply rate of the slurry from the second tank to the first tank includes a step of maintaining the supply rate of the slurry from the second tank to the first tank when the temperature of the first tank falls within a predetermined normal temperature range and the temperature of the second tank is higher or lower than the predetermined normal temperature range.

10. 8. The method for controlling a supply amount of slurry for an electrode according to claim 7, wherein the step of controlling the supply amount of the slurry from the second tank to the first tank includes the step of increasing the supply amount of the slurry from the second tank to the first tank when the temperature of the first tank is higher or lower than a predetermined normal temperature range and the temperature of the second tank falls within the predetermined normal temperature range.

11. 8. The method for controlling a supply amount of slurry for an electrode according to claim 7, wherein the step of controlling the supply amount of the slurry from the second tank to the first tank includes the step of increasing the supply amount of the slurry from the second tank to the first tank when the temperature of the first tank is higher than a predetermined normal temperature range and the temperature of the second tank is lower than the predetermined normal temperature range.

12. 8. The method for controlling a supply rate of a slurry for an electrode according to claim 7, wherein the step of controlling the supply rate of the slurry from the second tank to the first tank includes the step of increasing the supply rate of the slurry from the second tank to the first tank when the temperature of the first tank is lower than a predetermined normal temperature range and the temperature of the second tank is higher than the predetermined normal temperature range.

13. 8. The method for controlling a supply rate of slurry for an electrode according to claim 7, wherein the step of controlling the supply rate of the slurry from the second tank to the first tank includes a step of maintaining the supply rate of the slurry from the second tank to the first tank when the temperature of the first tank is higher than a predetermined normal temperature range and the temperature of the second tank is higher than the predetermined normal temperature range.

14. 8. The method for controlling a supply rate of slurry for an electrode according to claim 7, wherein the step of controlling the supply rate of the slurry from the second tank to the first tank includes a step of maintaining the supply rate of the slurry from the second tank to the first tank when the temperature of the first tank is lower than a predetermined normal temperature range and the temperature of the second tank is lower than the predetermined normal temperature range.

15. 15. The method for controlling a supply amount of electrode slurry according to claim 8, wherein the predetermined normal temperature range is a temperature range that is preset to be suitable for coating the slurry.

16. An electrode slurry supply device that performs the electrode slurry supply amount control method according to claim 1 or 7, a coater for coating the slurry; a first tank that supplies the slurry to the coater; a second tank for storing the slurry and supplying it to the first tank; a pipe connecting the first tank and the second tank; and a valve provided in the piping.

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