Battery cell pressurization device and battery cell manufacturing method

Abstract

The present invention relates to a battery cell pressurizing device and a battery cell manufacturing method using the same, and more specifically to a battery cell pressurizing device for uniformly pressurizing battery cells and a battery cell manufacturing method using the same. According to one embodiment of the present invention, a battery cell pressurizing device is provided which includes a first end plate located on one side; a second end plate located on the other side opposite to the first end plate; a pressurizing plate that moves the first end plate in the direction in which the plurality of battery cells are stacked to pressurize the plurality of battery cells arranged between the first end plate and the second end plate; a first pressurizing member provided to pressurize the central part of the pressurizing plate and pressurize the central part of the first end plate through the pressurizing plate; and a second pressurizing member and a third pressurizing member that pressurize one side and the other side, respectively, with respect to the center of the first end plate.

Description

Technical Field

[0005] , ,

[0006]

[0001] The present invention relates to a battery cell pressurizing device and a battery cell manufacturing method using the same, and more specifically, to a battery cell pressurizing device for uniformly pressurizing a battery cell and a battery cell manufacturing method using the same.

Background Art

[0002] A secondary battery is a battery that can be repeatedly used through a discharging process of converting chemical energy into electrical energy and a charging process of converting electrical energy into chemical energy.

[0003] Secondary batteries can include nickel-cadmium (Ni-Cd) batteries, nickel-metal hydride (Ni-MH) batteries, lithium-metal batteries, lithium-ion (Li-Ion) batteries, and lithium-ion polymer batteries (Li-Ion Polymer Battery, hereinafter referred to as "LIPB"), etc.

[0004] Lithium secondary batteries have a cycle life of about 500 times or more and a short charging time of about 1 hour to 2 hours, and can be made lighter because they are about 30% to 40% lighter than nickel-metal hydride batteries. Among existing secondary batteries, they have the highest voltage per unit cell (30V to 37V) and excellent energy density, so they can have characteristics optimized for mobile devices.

[0005] As a lithium secondary battery, a pouch-type battery cell in which an electrode assembly is sealed with a pouch made of an aluminum sealing material is widely used.

[0006] Generally, an electrode assembly, which is an internal component of a battery cell, is manufactured as an integrated unit formed by gathering units laminated in a three-layer structure of a positive electrode / separator / negative electrode, or a five-layer structure of a positive electrode / separator / negative electrode / separator / positive electrode or a negative electrode / separator / positive electrode / separator / negative electrode. And such an electrode assembly is housed in a pouch case which is a sealing material. The pouch type houses the electrode assembly in a pouch made of a flexible polymer material with an irregular shape.

[0007] The pouch, which is the case for a pouch-type battery cell, is manufactured by forming a cup-shaped housing for housing the electrode assembly in a pouch film made of a flexible material. That is, once a housing with a space for housing the electrode assembly is formed in the pouch film, the electrode assembly is placed in the housing space of the housing, and the edges are sealed to manufacture a secondary battery. Such a pouch film consists of multiple layers, such as an outer coating layer, a metal barrier layer, and an internal adhesive layer.

[0008] Figure 1 is a separated perspective view showing the configuration of a conventional pouch-type secondary battery.

[0009] For example, as shown in Figure 1, the electrode assembly 50 is housed in a housing section 21b1 formed in the lower pouch film 21b. At this time, the electrode assembly 50 has leads 51 and 52, and the leads can be divided into a positive electrode lead 51 and a negative electrode lead 52. With the electrode assembly 50 housed in the housing section 21b1, the electrolyte is injected, and the edges 21b2 of the upper pouch film 21a and the lower pouch film 21b are heat-sealed. Thereafter, charging and discharging (activation process) and inspection processes can be carried out.

[0010] In pouch-type battery cells, the electrolyte inside the pouch reacts during charging, generating gas and causing the pouch to swell outwards. Therefore, to increase the battery capacity, a squeezing process is necessary, which involves pressurizing and compressing the pouch containing the battery cell. This squeezing process ensures that the internal spacing of the electrode assembly of the battery cell is as compact as possible, allowing the electrolyte inside the pouch to spread evenly and thus increasing the battery capacity. A pressurizing device is used to pressurize the pouch-type battery cell during this squeezing process.

[0011] Furthermore, the pressurizing device can be used as a formation jig to activate pouch-type battery cells by pressurizing them at a constant pressure. A jig is a device that pressurizes multiple battery cells through multiple partition plates, and the process of using such a jig to control temperature and pressure in addition to current and capacity during the activation process is called the formation process.

[0012] Figure 2 is a plan view of the pressurizing device of the prior patent.

[0013] As shown in Figure 2, the conventional pressurizing device 10 includes a first end plate 13 and a second end plate 12 at the front and rear, respectively, and is configured to house multiple battery cells 20 arranged in the front-rear direction (X-axis direction) between the end plates 13 and 12. Multiple partition plates 14 are provided between the first end plate 13 and the second end plate 12, and the battery cells 20 are positioned between the partition plates. The first end plate 13 receives the pressure transmitted from the pressurizing member 11 and can pressurize the multiple battery cells backward. Conversely, the pressurizing member 11 can be driven to move the first end plate 13 in the opposite direction of the pressurizing direction, thereby releasing the pressure on the multiple battery cells. The second end plate 12 plays the role of supporting the pressurized multiple battery cells forward.

[0014] Conventionally, pressurization was performed by using a single pressurizing member 11 with a servo motor to pressurize only the central part of the first end plate 13 and move the first end plate 13. In this case, the pressurizing force received by multiple battery cells 20 was concentrated on the central part of the first end plate 13, causing a difference in pressurizing force between the central part and the side parts, or the pressurizing force was concentrated on one of the side parts, making it easy for a difference in pressurizing force to occur on both sides in the Y-axis direction. Therefore, conventional pressurizing devices either applied uneven pressurization to multiple battery cells or caused uneven pressurization depending on the position of a single battery cell. Consequently, the battery capacity of pouch-type battery cells was not constant, and this increased the rate of defective battery cells with a low capacity that could not reach the standard battery capacity.

[0015] For example, Korean Published Patent No. 10-2022-0101269 (hereinafter referred to as the "prior patent") discloses a pressurized tray capable of pressurizing multiple battery cells and a battery cell activation device including the same.

[0016] Specifically, the first and second main plates of the prior patent pressurize and release multiple battery cells by the rotational movement of the drive shaft. In addition, four drive shafts are connected to the edge regions of each of the first and second main plates. Depending on the direction of rotation of the four drive shafts, the first and second main plates can be screwed together to move closer to each other or to move further apart.

[0017] However, in the prior patent, the pressurizing force is concentrated in the edge regions where the four drive shafts of the first and second main plates are located, making it prone to deviations in the pressurizing force applied to the center and sides of the first and second main plates. Furthermore, since the prior patent uses only one motor to rotate the four drive shafts, it has the limitation that it is impossible to control the pressurizing force to correct deviations even if deviations occur in the pressurizing force between the left and right sides of the first and second main plates.

[0018] For these reasons, conventional technology still suffers from the problem of unevenly pressurizing multiple battery cells, and it is particularly necessary to prevent lithium deposition phenomena that can occur due to differences in battery cell thickness and pressure. Therefore, there is an urgent need to develop technologies that can minimize defects that occur in such activation processes. [Overview of the project] [Problems that the invention aims to solve]

[0019] The present invention aims to solve the problems of conventional battery cell pressurization devices used in activation processes.

[0020] Through one embodiment of the present invention, we aim to provide a battery cell pressurizing device for pressurizing multiple battery cells with a uniform pressure, and a battery cell manufacturing method using the same.

[0021] Through one embodiment of the present invention, we aim to provide a battery cell pressurization device and a battery cell manufacturing method that can eliminate the phenomenon of uneven battery cell pressurization between the center and one side, thereby preventing lithium deposition due to pressurization imbalance. [Means for solving the problem]

[0022] To achieve the aforementioned objectives, according to one embodiment of the present invention, a battery cell pressurizing device is provided, comprising: a first end plate located on one side; a second end plate located on the other side opposite to the first end plate; a pressurizing plate that pressurizes a plurality of battery cells arranged between the first end plate and the second end plate by moving the first end plate in the direction in which the plurality of battery cells are stacked; a first pressurizing member provided to pressurize the central part of the pressurizing plate and pressurize the central part of the first end plate through the pressurizing plate; a second pressurizing member provided to pressurize one side of the first end plate independently of the first pressurizing member with respect to the center of the first end plate; and a third pressurizing member provided to pressurize the other side of the first end plate independently of the first pressurizing member with respect to the center of the first end plate.

[0023] The second pressing member and the third pressing member may be provided to directly press the first end plate at positions deviated from the pressing plate on both sides.

[0024] The second pressing member and the third pressing member may be provided to press the pressing plate on both sides of the pressing plate with reference to the center of the pressing plate.

[0025] Each of the first pressing member, the second pressing member, and the third pressing member may include a pressing rod whose length is variable and a driving unit that is driven to vary the length of the pressing rod.

[0026] A first main frame provided outside the first end plate and having a fixing portion to which the driving unit of the pressing member is fixed; and a second main frame provided outside the second end plate and forming a pressing space between the first end plate and the second end plate together with the first main frame are preferably provided.

[0027] The first main frame and the second main frame may be fixed.

[0028] When the first end plate is pressed and moved by the first pressing member, the pressing rods of the second pressing member and the third pressing member are preferably connected to the first end plate or the pressing plate so that their lengths are variably passive.

[0029] That is, when pressing is performed through the pressing rod of the first pressing member, it is preferable that pressing is not performed through the pressing rods of the second pressing member and the third pressing member.

[0030] The pressing rods of the second pressing member and the third pressing member may be connected to the first end plate or the pressing plate only when pressing the first end plate.

[0031] The drive unit for the first pressurizing member may include a servo motor that is capable of precisely controlling the travel distance of the pressurizing rod of the first pressurizing member.

[0032] The drive unit and pressure rod of the second and third pressure members are preferably a hydraulic cylinder and a cylinder rod that is movable relative to the hydraulic cylinder.

[0033] A control unit may be included to control the operation of the drive unit of the pressurizing member.

[0034] The control unit can control the second and third pressurizing members to pressurize the first end plate after the first pressurizing member has pressed the first end plate.

[0035] This may include a pressure sensing unit provided to measure the pressure applied to the battery cell.

[0036] Preferably, the control unit controls the operation of the drive unit of the pressurizing member based on the output of the pressure sensing unit.

[0037] The control unit can control the operation of the drive unit of the pressurizing member so that the first end plate moves a predetermined distance from its initial position and is pressurized.

[0038] The control unit can control the operation of the drive unit for the first pressurizing member and the drive unit for the second pressurizing member so as to eliminate minute displacement differences that occur between the center and both sides of the first end plate when the first pressurizing member pressurizes the center of the first end plate or the second end plate.

[0039] The first end plate may include a distance measuring unit provided for measuring the moved displacement of one side and the other side.

[0040] The aforementioned pressure plate preferably includes ribs that extend from the center to both sides, with the protruding height decreasing as you move in the direction extending from the center.

[0041] The second and third pressurizing members may be provided so as to be connected to the pressurizing plate on the outer sides of both sides of the rib.

[0042] To achieve the aforementioned objectives, according to one embodiment of the present invention, a battery cell manufacturing method is provided that utilizes a battery cell pressurizing device having a first end plate, a second end plate, and a pressurizing plate, comprising: a central pressurizing step in which a first pressurizing member pressurizes the central part of the pressurizing plate to pressurize a plurality of battery cells provided between the first end plate and the second end plate through the pressurizing plate; a one-side pressurizing step in which the second pressurizing member pressurizes one side of the first end plate with respect to its center to pressurize the plurality of battery cells independently of the first pressurizing member; and an other-side pressurizing step in which a third pressurizing member pressurizes the other side of the first end plate with respect to its center to pressurize the plurality of battery cells independently of the first pressurizing member.

[0043] It is preferable that the one-side pressurization stage and the other-side pressurization stage be performed after the completion of the central pressurization stage.

[0044] It is preferable that the pressurization step on one side and the pressurization step on the other side are performed simultaneously. [Effects of the Invention]

[0045] Through one embodiment of the present invention, a battery cell pressurizing apparatus and a battery cell manufacturing method can be provided that allows for uniform pressurization of multiple battery cells through a second pressurizing member and a third pressurizing member, which are provided to pressurize one side and the other side of the first end plate or the second end plate independently of the first pressurizing member, thereby effectively reducing the defect rate that occurs during the battery cell activation process.

[0046] Through one embodiment of the present invention, a battery cell pressurizing device and a battery cell manufacturing method can be provided that can achieve more complete and uniform pressurization by sensing and compensating for minute displacement differences between one side and the other side of the first end plate.

[0047] Through one embodiment of the present invention, it is possible to provide a battery cell pressurizing device and a battery cell manufacturing method that can minimize the deviation of the pressurizing force applied to both sides of multiple battery cells, manufacture battery cells with a certain specification (battery capacity), and effectively reduce the defect rate that occurs in the battery cell activation process.

[0048] Through one embodiment of the present invention, it is possible to provide a battery cell pressurizing device and a battery cell manufacturing method that can stably maintain a uniformly pressurized state of battery cells for a long period of time. [Brief explanation of the drawing]

[0049] [Figure 1] This is a separated perspective view showing the configuration of a conventional pouch-type battery cell.

[0050] [Figure 2] This is a plan view showing the configuration of a pressurizing device for pressurizing conventional pouch-type battery cells.

[0051] [Figure 3] This is a schematic plan view showing the configuration of a battery cell pressurizing device according to one embodiment of the present invention.

[0052] [Figure 4] This is a conceptual diagram schematically showing a partial configuration of a battery cell pressurizing device according to one embodiment of the present invention.

[0053] [Figure 5] This is a schematic vertical cross-sectional view showing a battery cell pressurization device according to one embodiment of the present invention.

[0054] [Figure 6]This is a schematic perspective view showing a partial configuration of a battery cell pressurization device according to one embodiment of the present invention.

[0055] [Figure 7] This is a schematic plan view showing the configuration of a battery cell pressurizing device according to another embodiment of the present invention.

[0056] [Figure 8] This is a schematic plan view showing the configuration of a battery cell pressurizing device according to yet another embodiment of the present invention.

[0057] [Figure 9] This is a schematic plan view showing the configuration of a battery cell pressurizing device according to yet another embodiment of the present invention. [Modes for carrying out the invention]

[0058] A pouch molding apparatus according to one embodiment of the present invention will be described in detail below with reference to the attached drawings.

[0059] Figure 3 is a schematic plan view showing the configuration of a battery cell pressurizing device 100 according to one embodiment of the present invention, Figure 4 is a schematic block diagram showing a partial configuration of the battery cell pressurizing device 100 according to one embodiment of the present invention, Figure 5 is a schematic vertical cross-sectional view showing the configuration of the battery cell pressurizing device 100 according to one embodiment of the present invention, and Figure 6 is a schematic perspective view showing a partial configuration of the battery cell pressurizing device.

[0060] A battery cell pressurizing device 100 according to one embodiment of the present invention is a device for pressurizing a plurality of battery cells 20 arranged in one direction. Here, the plurality of battery cells 20 may be arranged in an upright manner on a base plate 193. In other words, the battery cells 20 may be inserted between partition plates 192. Here, "one direction" may be the direction in which the first end plate 111 and the second end plate 112 face each other (X-axis direction).

[0061] The battery cell pressurizing device 100 may include a first end plate 111 and a second end plate 112.

[0062] The first end plate 111 is located on one side of the stacked battery cells 20. The first end plate 111 is provided to pressurize one side of the stacked or arranged battery cells 20 in one direction.

[0063] The second end plate 112 is located on the other side of the plurality of battery cells 20. The second end plate 112 may be provided to support the other side of the plurality of battery cells 20 that are pressurized by the first end plate 111.

[0064] The first end plate 111 and the second end plate 112 can have one surface facing the battery cell 20 that corresponds to or is larger than the size of the multiple battery cells 20. That is, the first end plate 111 and the second end plate 112 can have a surface that can face the central part and both sides of the battery cell 20.

[0065] The first end plate 111 may be formed to be larger than the second end plate 112. For example, since the first end plate 111 is provided to pressurize multiple battery cells 20, forming the first end plate 111 larger than the second end plate 112 may be advantageous for precisely performing compensatory control to reduce the deviation in pressurized force between the center and both sides of the first end plate 111.

[0066] The battery cell pressurizing device 100 may include a pressurizing plate 120. The pressurizing plate 120 may be made of a metal material with sufficient rigidity to stably pressurize a plurality of battery cells 20.

[0067] The pressure plate 120 is provided to move the first end plate 111 in the direction in which the multiple battery cells 20 are stacked. The pressure plate 120 may have a structure connected to the first end plate 111. That is, the pressure plate 120 is pressurized by the pressurizing members 131, 132, and 133, which will be described later, and at this time, the pressurizing force can be transmitted to the first end plate 111, which is connected to the pressure plate 120. As an example, the pressure plate may be configured to face the rear of the first end plate when pressurized, or it may be configured to be integrally formed with the first end plate.

[0068] The battery cell pressurizing device 100 of the present invention includes a first pressurizing member 131. The first pressurizing member 131 is provided to pressurize the central portion of the pressurizing plate 120. That is, by pressurizing the central portion of the pressurizing plate 120, the first pressurizing member 131 can transmit pressurizing force to the central portion of the first end plate 111. At this time, the central portion of the pressurizing plate 120 may be positioned to correspond to the central portion of the first end plate 111.

[0069] The first pressurizing member 131 may include a first pressurizing rod 131a that is movable in both directions. The first pressurizing member 131 may include a first drive unit 131b. The first drive unit 131b is connected to the first pressurizing rod 131a and can generate a force to move the first pressurizing rod 131a in both directions. For example, the first drive unit 131b may be configured to move the first pressurizing rod 131a in the direction in which the plurality of battery cells 20 are stacked.

[0070] The first pressurizing member 131 may include a servo motor connected to the first pressurizing rod 131a. That is, the drive unit of the first pressurizing member 131 may include a servo motor or a servo cylinder containing the servo motor. Therefore, the movement displacement of the first end plate 111, which is pressurized by the first pressurizing member 131, can be precisely controlled.

[0071] The battery cell pressurizing device 100 preferably includes a second pressurizing member 132. The second pressurizing member 132 is provided to pressurize one side (left side) of the first end plate 111 with respect to its center. The second pressurizing member 132 is provided to pressurize the first end plate 111 independently of the first pressurizing member 131.

[0072] The second pressurizing member 132 can transmit pressurizing force to one side of multiple battery cells 20 by pressurizing one side of the first end plate 111. Here, one side may mean the positive (+) direction portion with respect to the center of the Y-axis direction of the first end plate 111 or the second end plate 112.

[0073] The second pressurizing member 132 may include a second pressurizing rod 132a in the positive (+) direction of the Y-axis, which is provided to be movable in both directions. The second pressurizing member 132 may also include a second drive unit 132b. The second drive unit 132b is connected to the second pressurizing rod 132a and can generate a force to move the third pressurizing rod in both directions.

[0074] The second drive unit 132b may be configured to move the second pressure rod 132a in the direction in which the plurality of battery cells 20 are stacked. The second pressure member 132 may include a one-sided hydraulic cylinder (see Figure 6) as a drive unit for moving the second pressure rod.

[0075] The battery cell pressurizing device 100 preferably includes a third pressurizing member 133. The third pressurizing member 133 in the negative (-) direction of the Y-axis may be provided to pressurize the other side (right side) of the first end plate 111 with respect to its center. The third pressurizing member 133 is preferably provided to pressurize the first end plate 111 independently of the first pressurizing member 131.

[0076] The third pressurizing member 133 can transmit pressurizing force to the other side of the multiple battery cells 20 by pressurizing the other side of the first end plate 111. Here, the other side may mean the negative (-) direction portion with respect to the center in the Y-axis direction of the first end plate 111 or the second end plate 112.

[0077] The third pressurizing member 133 may include a third pressurizing rod 133a that is movable in both directions. The third pressurizing member 133 may also include a third drive unit 133b. The third drive unit 133b is connected to the third pressurizing rod 133a and can generate a force to move the third pressurizing rod 133a in both directions. As an example, the third pressurizing member 133 may include a hydraulic cylinder on the other side (see Figure 6) as a drive unit for moving the third pressurizing rod.

[0078] Preferably, the second and third pressurizing members are provided in the same form and arranged symmetrically around the first pressurizing member.

[0079] The battery cell pressurizing device 100 includes a first pressurizing member 131 and second and third pressurizing members 132 and 133, which are provided to pressurize one side and the other side of the first end plate 111 independently of the first pressurizing member 131. Therefore, the pressurizing force can be uniformly applied to the central and both sides of multiple battery cells 20. Furthermore, a uniform pressurizing force can be applied to the entire single battery cell 20. Therefore, positional pressure deviations among battery cells can be eliminated.

[0080] Accordingly, the battery cell pressurization device 100 according to this embodiment can effectively solve the problem of battery cell defects during the activation process.

[0081] As shown in Figure 6, the ends of the second pressure rod 132a and the third pressure rod 133a can be connected to one side (left side) and the other side (right side) of the first end plate 111 or the second end plate 112.

[0082] Furthermore, when the first pressure rod 131a of the first pressure member 131 pressurizes the central part of the pressure plate 120 and moves the first end plate 111, the second pressure rod 132a and the third pressure rod 133a can each be provided to be passively moved by the movement of the first end plate 111 or the second end plate 112.

[0083] For example, the second pressure rod 132a and the third pressure rod 133a may be configured to always be connected to the first end plate 111. Contrary to the illustration, the second pressure rod 132a and the third pressure rod 133a may be configured to always be connected to the pressure plate 120. In the former case, the second and third pressure rods directly pressurize both sides of the first end plate 111, while in the latter case, the second and third pressure rods indirectly pressurize both sides of the first end plate 111 by pressurizing both sides of the pressure plate 120.

[0084] Furthermore, the second pressure rod 132a and the third pressure rod 133a can be connected to the first end plate 111 or the pressure plate 120 only when pressurizing the first end plate 111.

[0085] For example, the second pressurizing member 131 may include a one-sided hydraulic cylinder. The third pressurizing member 133 may include a other-sided hydraulic cylinder. In this case, the second pressurizing rod 132a and the third pressurizing rod 133a may each be piston rods of a hydraulic cylinder. That is, if the second pressurizing rod 132a and the third pressurizing rod 133a are piston rods connected to a piston inside the cylinder of a hydraulic cylinder, the piston rods can be passively moved by an external force when no hydraulic fluid pressure is applied inside the cylinder.

[0086] Pressurization can be achieved by increasing the length of the piston rod. In this case, the hydraulic cylinder is driven to increase the length of the piston rod. Conversely, the length of the piston rod can also be increased by an external force, such as a pulling force on the piston rod. In this case, the hydraulic cylinder does not need to be driven. Therefore, with the end of the piston rod connected to the first end plate or pressurizing plate, the length of the piston rod can be actively increased for pressurization or simply increased passively.

[0087] The battery cell pressurizing device 100 can first pressurize the central part of the multiple battery cells 20 by having the first pressurizing member 131 pressurize the pressurizing plate 120, and then pressurize both sides of the multiple battery cells 20 using the second pressurizing member 132 and the third pressurizing member 133. In this case, it is suitable for the second pressurizing rod 132a and the third pressurizing rod 133a of the second pressurizing member 132 and the third pressurizing member 133 to be passively movable by the movement of the first end plate 111 or the second end plate 112. For this reason, it is preferable to use hydraulic cylinders in which the piston rods can move freely by external force for the second pressurizing member 132 and the third pressurizing member 133.

[0088] Furthermore, the first pressurizing member needs to be provided to apply a continuous and constant pressure regardless of the increase in the length of the pressurizing rod. On the other hand, the second and third pressurizing members are auxiliary pressurizing means and need to be provided to apply pressure in specific situations or for specific lengths. For example, it is preferable that pressurization and maintenance are performed additionally through the second and third pressurizing members once pressurization is completed and maintained through the first pressurizing member. Therefore, it is preferable that the drive unit for the first pressurizing member and the drive units for the second and third pressurizing members are provided in different forms from each other.

[0089] Figure 7 is a schematic plan view showing the configuration of a battery cell pressurizing device 100A according to another embodiment of the present invention.

[0090] Referring to Figure 7, the battery cell pressurizing device 100A according to another embodiment shown in Figure 7 differs from the battery cell pressurizing device 100 shown in Figure 3 in that the second pressurizing member 132 and the third pressurizing member 133 may be configured to pressurize one side and the other side of the pressurizing plate 120 with respect to the center of the pressurizing plate 120. Through this, it may be configured to indirectly pressurize one side and the other side of the first end plate 111.

[0091] On the other hand, the battery cell pressurizing device 100 according to one embodiment of the present invention may include a control unit 113. The control unit 113 may be provided to control the operation of the first drive unit 131b, the second drive unit 132b, and the third drive unit 133b, respectively.

[0092] The control unit 113 can control the first drive unit 131b, the second drive unit 132b, and the third drive unit 133b so that the first end plate 111 moves a predetermined distance from its initial position to pressurize the multiple battery cells 20.

[0093] For example, the control unit 113 can measure the distance the first end plate 111 has moved from its initial position to a predetermined distance, and control the first drive unit 131b, the second drive unit 132b, and the third drive unit 133b to stop pressurizing the first end plate 111 once it has moved to the predetermined distance and pressurized. In other words, pressurization can be maintained.

[0094] However, the method is not necessarily limited to this type, and the first end plate 111 may be structurally designed to be movable only up to a predetermined distance.

[0095] For example, the control unit 113 can set a predetermined travel distance at which the first end plate 111 or the second end plate 112 pressurizes the multiple battery cells 20 with an appropriate level of pressure that can provide a reference battery capacity. A pressure sensing unit 170 may be provided for this purpose. That is, it can be configured to stop pressurizing once the set pressure is reached and then maintain the pressurization.

[0096] The control unit 113 can control the operation of the second drive unit 132b and the third drive unit 133b to eliminate minute displacement differences that occur between the center and both sides of the first end plate 111 or the second end plate 112 after the first pressurizing member 131 has pressurized the first end plate 111.

[0097] The control unit 113 can control the second drive unit 132b and the third drive unit 133b so that after the first pressurizing member 131 pressurizes the central part of the pressurizing plate 120, the second pressurizing rod 132a and the third pressurizing rod 133a pressurize both sides of the first end plate 111 or the second end plate 112. Accordingly, the battery cell pressurizing device 100 of the present invention can uniformly pressurize multiple battery cells.

[0098] The battery cell pressurizing device 100 may further include a pressure sensing unit 170. The pressure sensing unit 170 may be configured to measure the pressure applied to a plurality of battery cells 20.

[0099] The control unit 113 can pressurize the first end plate 111 by deciding whether to increase or decrease the pressurizing force based on the pressure sensing unit 170 and the measured pressure value. The control unit 113 can control the operation of the first drive unit 131b, the second drive unit 132b, and the third drive unit 133b so that the first end plate 111 can be pressurized up to a preset pressure.

[0100] For example, the control unit 113 can set a pressure so that multiple battery cells 20 have a reference battery capacity. The control unit 113 operates the first drive unit 131b, the second drive unit 132b, and the third drive unit 133b so that the first pressurizing rod 131a, the second pressurizing rod 132a, and the third pressurizing rod 133a pressurize the first end plate 111 or the second end plate 112 until the pressure measured by the pressure sensing unit 170 reaches a preset pressure.

[0101] Meanwhile, the control unit 113 controls the operation of the first pressurizing member based on the output of the pressure sensing unit 170 to maintain the applied pressure, and thereafter the control unit 113 can maintain the applied pressure by controlling the operation of the second and third pressurizing members based on the outputs of the distance measuring units 161 and 162.

[0102] Therefore, since three points are formed that provide and maintain the applied pressure, the applied pressure can be maintained uniformly and stably during the activation process.

[0103] As shown in Figure 6, the pressure plate 120 may include ribs 120a. The ribs 120a may extend from the center to both sides, with the thickness of the horizontal cross-section gradually decreasing in the direction of extension. The ribs 120a may be formed extending to the left and right at the rear of the pressure plate, with the protruding height decreasing from the center to the left and right. Such ribs 120a are provided to reinforce the mechanical rigidity against the pressure applied by the first pressure member 131 to the central part of the pressure plate 120, and may be formed so that the pressure applied to the central part is sufficiently transmitted to both sides of the pressure plate through the ribs. Therefore, the greater the pressure applied by the first pressure member 131, the better the thickness of the horizontal cross-section. Consequently, the pressure plate 120 has the advantage of being able to extend the transmission range of the pressure applied by the first pressure member 131 to both sides through the ribs 120a.

[0104] A fixing groove H may be formed in the rib 120a into which the end of the first pressure rod 131a of the first pressure member 131 can be inserted. At this time, the end of the first pressure rod 131a of the first pressure member 131 can be fixed in the state inserted in the fixing groove H. Any commonly used fixing method such as adhesive, welding, or screw connection can be applied. That is, the first pressure rod 131a and the pressure plate 120 can be connected to each other and configured to move as a single unit.

[0105] The battery cell pressurizing device 100 may comprise a first main frame 151 and a second main frame 152. The first main frame 151 and the second main frame 152 may be arranged to form a certain space inside them so that a plurality of battery cells 20 can be housed in the X-axis direction. That is, the first main frame 151 and the second main frame 152 may be separated from each other by a predetermined distance to form a space in which a plurality of battery cells 20 are arranged. The first main frame and the second main frame may be in a fixed configuration.

[0106] The first mainframe 151 and the second mainframe 152 may have a hexahedral shape.

[0107] The first main frame 151 may have a plurality of fixing holes F or fixing parts provided for fixing the first pressurizing member 131, the second pressurizing member 132, and the third pressurizing member 133, respectively. For example, a drive unit for the pressurizing member may be fixed to the first main frame 151, and a pressurizing rod may be provided to move forward and backward relative to the fixed drive unit.

[0108] As shown in Figure 5, the battery cell pressurizing device 100 may be equipped with a plurality of column shafts 153. Both ends of the plurality of column shafts 153 may be connected to the first main frame 151 and the second main frame 152, respectively. That is, the plurality of column shafts 153 may be provided to connect and fix the first main frame 151 and the second main frame 152. The plurality of column shafts 153 may be provided to set a separation distance between the first main frame 151 and the second main frame 152. Such a separation distance may be set considering the volume of the plurality of battery cells 20 to be mounted.

[0109] Furthermore, the battery cell pressurizing device 100 may further include a plurality of plate guide shafts 154 that penetrate the first end plate 111 to guide the movement direction of the first end plate 111. The plurality of plate guide shafts 154 may extend along the stacking direction or arrangement direction (X-axis direction) of the plurality of battery cells 20. Both ends of the plurality of guide shafts 154 may be connected to the first main frame 151 and the second main frame 152, respectively.

[0110] Furthermore, the battery cell pressurizing device 100 may include a base plate 193 on which a plurality of battery cells 20 can be mounted. The base plate 193 may be located between the first main frame 151 and the second main frame 152. The base plate 193 may have a plate shape with a rectangular plane. The base plate 193 may be arranged so that its wide surface faces vertically.

[0111] Furthermore, the battery cell pressurizing device 100 may include a plurality of partition plates 192 between the first end plate 111 and the second end plate 112. Battery cells 20 may be interposed between the plurality of partition plates 192. That is, the plurality of battery cells 20 may be configured to pressurize the battery cells 20 interposed between the plurality of partition plates 192 upon receiving the pressurized force transmitted to the first end plate 111.

[0112] Furthermore, the battery cell pressurizing device 100 may further comprise a plurality of sub-guide shafts 155 provided to guide the movement direction of the partition plate 192 and the first end plate 111. The plurality of sub-guide shafts 155 may be provided so as to penetrate the partition plate 192 and the first end plate 111.

[0113] As shown in Figure 3, the battery cell pressurizing device 100 may further include a support plate 191. The support plate 191 may be movably connected to a first main frame 151 or a second main frame 152. The support plate 191 may have a groove (not shown) into which a movable shaft can be inserted. The movable shaft can be inserted into the groove of the support plate 191. Using such a structure, the support plate 191 may be able to move in the front-rear direction along the movable shaft.

[0114] Furthermore, the battery cell pressurizing device 100 may further include an elastic member 180. The elastic member 180 may be provided to elastically support the space between the support plate 191 and the second end plate 112. That is, the elastic member 180 may be interposed between the support plate 191 and the second end plate 112. The elastic member 180 may be provided to buffer the force transmitted from the first end plate 111 or the second end plate 112 and transmit it to the support plate 191. The elastic member 180 may be, for example, a spring member having a predetermined elastic force. For example, the battery cell pressurizing device 100 may comprise a plurality of elastic members 180.

[0115] The aforementioned pressure sensing unit 170 may be configured to measure the pressure applied to the support plate 191 through a plurality of pressurized battery cells 20. The pressure sensing unit 170 may have a structure in which one end is connected to the support plate 191 and the other end is connected to the second main frame 152. Here, the pressure sensing unit 170 may include a pressure sensor 170a that measures the pressurized force and outputs the value as an electrical signal. For example, the pressure sensing unit 170 may be a load cell on a strain gauge substrate. For example, the pressure sensor of the pressure sensing unit 170 may support one surface of the support plate 191. Accordingly, the pressure sensing unit 170 can output as an electrical signal the pressurized force that the support plate 191 transmits to the pressure sensor (e.g., strain gauge).

[0116] Therefore, by including the elastic member 180, the support plate 191, and the pressure sensing unit 170, there is an advantage in that the pressurizing force applied to multiple battery cells 20 can be effectively measured.

[0117] Figure 8 is a schematic plan view showing the configuration of a battery cell pressurizing device 100B according to yet another embodiment of the present invention.

[0118] The battery cell pressurizing device 100B according to this embodiment may further include a first distance measuring unit 161 and a second distance measuring unit 162.

[0119] Specifically, the first distance measuring unit 161 and the second distance measuring unit 162 may be configured to measure the displacement of one side and the other side of the first end plate 111. For example, the first distance measuring unit 161 and the second distance measuring unit 162 can each measure the displacement of one side (left side) and the other side (right side) of the first end plate 111. At this time, the control unit 113 can control the operation of the first drive unit 131b, the second drive unit 132b, and the third drive unit 133b based on the measured displacement values. Therefore, it is possible to precisely match the pressurized displacement on both sides as well as the central part.

[0120] For example, the first distance measuring unit 161 and the second distance measuring unit 162 may be laser rangefinders. Here, the laser rangefinder may include a device that generates a laser, a photodetector that senses the laser reflected back from the target, and a counter for time calculation. The principle of distance measurement in a laser rangefinder may consist of emitting a highly directional laser towards the target to be measured, and then calculating the distance by measuring the time it takes for the laser to reflect back from the target.

[0121] The control unit 113 can control the operation of the second drive unit 132b and the third drive unit 133b to eliminate minute displacement differences that occur between one side and the other side with respect to the center of the first end plate 111, based on the displacement values ​​measured by the first distance measuring unit 161 and the second distance measuring unit 162.

[0122] Therefore, the battery cell pressurizing device 100B of the present invention, by further including a first distance measuring unit 161 and a second distance measuring unit 162, can not only measure the movement displacement of the first end plate 111, but also sense the minute displacement difference between one side and the other side of the first end plate 111, and precisely control the first pressurizing member 131, the second pressurizing member 132, and the third pressurizing member 133 based on the sensed displacement value. This has the advantage of enabling more complete and uniform pressurization, thereby improving the quality of the battery cells.

[0123] On the other hand, the battery cell pressurizing device 100B according to this embodiment may be equipped with two or more pressure sensing units 171, 172.

[0124] Two or more pressure sensing units 171, 172 may be provided between the support plate 191 and the second main frame 152. The two or more pressure sensing units 171, 172 may be connected on both sides (both sides in the Y-axis direction) with respect to the center of the support plate 191 in order to measure the deviation of the applied pressure applied on both sides (left and right sides) with respect to the center of the multiple battery cells 20.

[0125] Each of the two or more pressure sensing units 171, 172 may be configured to measure the applied pressure transmitted from one side in the positive (+) direction of the Y-axis and the other side in the negative (-) direction of the Y-axis, respectively, with respect to the center of the support plate 191. The system may include a first pressure sensing unit 171 and a second pressure sensing unit 172 for measuring the applied pressure transmitted from one side and the other side, respectively, with respect to the center of the support plate 191.

[0126] The control unit 113 can control the operation of the first pressurizing member 131, the second pressurizing member 132, and the third pressurizing member 133 based on the pressure values ​​output as electrical signals from two or more pressure sensing units 171, 172, respectively. For example, if the pressure value measured by the first pressure sensing unit 171 on one side of the support plate 191 differs from the pressure value measured by the second pressure sensing unit 172 on the same side, the control unit 113 can control the operation of at least one of the second pressurizing member 132 and the third pressurizing member 133 to minimize the deviation in applied pressure.

[0127] Therefore, the deviation of the pressure applied to both sides of multiple battery cells 20 can be measured, and the control unit 113 can operate and control the second pressurizing member 132 and the third pressurizing member 133 so as to minimize the deviation of the pressure. Accordingly, the battery cell pressurizing device 100B of the present invention can minimize the deviation of the pressure applied to both sides of multiple battery cells 20, the battery cell pressurizing device 100B of the present invention can manufacture battery cells 20 with a certain specification (battery capacity), and can effectively reduce the defect rate that occurs in the activation process of the battery cells 20.

[0128] Figure 9 is a schematic plan view showing the configuration of a battery cell pressurizing device 100 according to yet another embodiment of the present invention.

[0129] This embodiment differs in that the first end plate 111 and the second end plate 112 are configured to pressurize the multiple battery cells 20 on both sides of the multiple battery cells 20.

[0130] In other words, in the battery cell pressurizing device 100C shown in Figure 9, which is another embodiment of the present invention, the pressurizing configuration for pressurizing the first end plate 111 and the second end plate 112 may be provided not only on one side of the first end plate 111 or the other side of the second end plate 112, but on both sides.

[0131] In other words, the pressurized configuration, consisting of a first pressurized plate 121, a first pressurized member 131, a second pressurized member 132, and a third pressurized member 133, is provided on one side of the first end plate 111, while the second pressurized plate 122, a fourth pressurized member 134, a fifth pressurized member 135, and a sixth pressurized member 136 may be provided on the other side of the second end plate 112.

[0132] The first pressure plate 121, the first pressure member 131, the second pressure member 132, and the third pressure member 133 may be arranged to apply pressure to the first end plate 111 in the direction toward the plurality of battery cells 20.

[0133] The second pressure plate 122, the fourth pressure member 134, the fifth pressure member 135, and the sixth pressure member 136 may be provided to pressurize the second end plate 112 in the direction toward the plurality of battery cells 20.

[0134] Furthermore, when compared with the battery cell pressurizing device 100 in Figure 3, the battery cell pressurizing device 100C in Figure 9 may further include a second pressurizing plate 122, a fourth pressurizing member 134, a fifth pressurizing member 135, and a sixth pressurizing member 136. The remaining components may be identical or similar to those of the embodiment described in Figure 3.

[0135] Therefore, by applying pressure to multiple battery cells 20 in both directions, there is an advantage in that the pressure deviation between battery cells 20 located at the center and end of the stacking direction or arrangement direction of the multiple battery cells 20 can be reduced.

[0136] A battery cell manufacturing method according to one embodiment of the present invention can be carried out using the pressurizing device described above. This embodiment may include a central pressurizing stage and a side pressurizing stage. The side pressurizing stage may include a one-side pressurizing stage and a other-side pressurizing stage.

[0137] The central pressurization stage can be described as the stage in which the first pressurizing member pressurizes the central part of the pressurizing plate, thereby pressurizing the multiple battery cells provided between the first end plate and the second end plate through the pressurizing plate.

[0138] The one-side pressurization stage can be described as the stage in which the second pressurizing member pressurizes one side of the first end plate with respect to its center, thereby pressurizing the plurality of battery cells independently of the first pressurizing member.

[0139] The other-side pressurization stage can be described as the stage in which the third pressurizing member pressurizes the other side of the first end plate with respect to the center, thereby pressurizing the plurality of battery cells independently of the first pressurizing member.

[0140] The drive unit for the first pressurizing member and the drive units for the first and second pressurizing members are different from each other. Therefore, when the entire pressurizing member is pressurized simultaneously, it is not easy to provide uniform pressurization. For this reason, it is preferable that the one-side pressurizing stage and the other-side pressurizing stage be performed after the completion of the central pressurizing stage.

[0141] Furthermore, the drive unit for the second pressurizing member and the drive unit for the third pressurizing member have the same configuration. Therefore, it is easy to provide uniform pressurization. Accordingly, it is preferable that the one-side pressurization stage and the other-side pressurization stage be performed simultaneously.

[0142] The battery cell manufacturing method of the present invention includes a central pressing step in which a first pressing member 131 pressurizes the central part of the pressing plate 120 in the direction in which the plurality of battery cells 20 are stacked (the negative (-) direction of the X axis). That is, by the first pressing member 131 pressing the central part of the pressing plate 120, the first end plate 111, which is indirectly connected to the pressing plate 120, moves, and such first end plate 111 directly or indirectly pressurizes the plurality of battery cells 20.

[0143] Once pressurization is complete, the jig formation process can be carried out while maintaining the pressurization. At this time, the battery cells may expand due to repeated charging and discharging, which can result in uneven pressure distribution across the entire battery cell.

[0144] According to this embodiment, three points are formed to provide and maintain the applied pressure, so the jig formation process can be effectively carried out. This eliminates deviations in the battery cells and, as a result, effectively prevents lithium deposition problems. [Industrial applicability]

[0145] This is described in the detailed description of the invention.

Claims

1. First end plate located on one side; A second end plate located on the opposite side from the first end plate; A pressurizing plate that pressurizes a plurality of battery cells positioned between the first end plate and the second end plate by moving the first end plate in the direction in which the plurality of battery cells are stacked; A first pressurizing member is provided to pressurize the central part of the pressurizing plate and pressurize the central part of the first end plate through the pressurizing plate; A second pressurizing member is provided to pressurize one side of the first end plate independently of the first pressurizing member, with respect to the center of the first end plate; and A battery cell pressurizing device, including a third pressurizing member provided to pressurize the other side of the first end plate independently of the first pressurizing member, with the center of the first end plate as the reference point.

2. The second pressurizing member and the third pressurizing member are The battery cell pressurizing device according to claim 1, further comprising a battery cell pressurizing device provided on both sides to directly pressurize the first end plate at a position away from the pressurizing plate.

3. The second pressurizing member and the third pressurizing member are The battery cell pressurizing device according to claim 1, wherein the device is provided to pressurize the pressurizing plate on both sides of the pressurizing plate with respect to the center of the pressurizing plate.

4. The battery cell pressurizing device according to any one of claims 1 to 3, wherein each of the first pressurizing member, the second pressurizing member, and the third pressurizing member includes a pressurizing rod of variable length and a drive unit driven for the variable length of the pressurizing rod.

5. A first main frame provided on the outside of the first end plate, having a fixing portion formed thereon where the drive units of the first pressurizing member, the second pressurizing member, and the third pressurizing member are fixed; and The battery cell pressurizing device according to claim 4, further comprising a second main frame provided on the outside of the second end plate, which forms a pressurized space between itself and the first main frame, the first end plate and the second end plate.

6. The battery cell pressurizing device according to claim 4, wherein when the first end plate is pressurized and moved by the first pressurizing member, the pressurizing rods of the second pressurizing member and the third pressurizing member are connected to the first end plate or the pressurizing plate in such a way that their lengths are passively variable.

7. The battery cell pressurizing device according to claim 4, wherein the pressurizing rods of the second pressurizing member and the third pressurizing member are connected to the first end plate or the pressurizing plate only when pressurizing the first end plate.

8. The battery cell pressurizing device according to claim 4, wherein the drive unit of the first pressurizing member includes a servo motor that is capable of precisely controlling the travel distance of the pressurizing rod of the first pressurizing member.

9. The battery cell pressurizing device according to claim 4, wherein the drive unit and the pressurizing rod of the second pressurizing member and the third pressurizing member, respectively, are a hydraulic cylinder and a cylinder rod that is movable relative to the hydraulic cylinder.

10. The battery cell pressurization device according to claim 4, further comprising a control unit for controlling the operation of the drive unit.

11. The battery cell pressurizing device according to claim 10, wherein the control unit controls the second pressurizing member and the third pressurizing member to pressurize the first end plate after the first pressurizing member has pressedurized the first end plate.

12. Includes a pressure sensing unit provided for measuring the pressure applied to the battery cell, The battery cell pressurizing device according to claim 10, wherein the control unit controls the operation of the drive unit based on the output of the pressure sensing unit.

13. The battery cell pressurizing device according to claim 10, wherein the control unit controls the operation of the drive unit so that the first end plate moves a predetermined distance from its initial position and is pressurized.

14. The control unit is The battery cell pressurizing device according to claim 13, wherein when the first pressurizing member pressurizes the center of the first end plate or the second end plate, the operation of the drive unit of the first pressurizing member and the drive unit of the second pressurizing member are controlled to eliminate minute displacement differences that occur between the center and both sides of the first end plate.

15. The battery cell pressurizing device according to claim 14, comprising a distance measuring unit for measuring the moved displacement of one side and the other side of the first end plate.

16. The aforementioned pressure plate is The battery cell pressurizing device according to claim 1, comprising ribs extending from the center to both sides, the height of which protrudes decreases as it goes in the direction extending from the center.

17. The battery cell pressurizing device according to claim 16, wherein the second pressurizing member and the third pressurizing member are provided to be connected to the pressurizing plate on the outer sides of both sides of the rib.

18. In a battery cell manufacturing method utilizing a battery cell pressurization device having a first end plate, a second end plate, and a pressurizing plate, Central pressurization step: The first pressurizing member pressurizes the central part of the pressurizing plate, thereby pressurizing the plurality of battery cells provided between the first end plate and the second end plate through the pressurizing plate; A one-side pressurizing step in which the second pressurizing member pressurizes one side of the first end plate with respect to its center, thereby pressurizing the plurality of battery cells independently of the first pressurizing member; and A battery cell manufacturing method comprising a third pressurizing member pressurizing the other side of the first end plate with respect to its center, thereby pressurizing the plurality of battery cells independently of the first pressurizing member.

19. The battery cell manufacturing method according to claim 18, wherein the one-side pressurization step and the other-side pressurization step are performed after the completion of the central pressurization step.

20. The battery cell manufacturing method according to claim 18 or 19, wherein the one-side pressurization step and the other-side pressurization step are performed simultaneously.

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