Laminating device for electrode foil of lithium metal secondary battery

Abstract

The present disclosure relates to a press-fitting device for an electrode foil of an all-solid-state secondary battery, the press-fitting device comprising an asymmetric press-fitting element which can accurately adjust a supply speed and a rolling speed while preventing damage to a metal foil, thereby improving uniformity and coating flatness of the electrode foil.

Description

Technical Field

[0001] The present disclosure relates to an apparatus capable of manufacturing an electrode foil assembly by pressing an electrode foil for a lithium metal battery. Background Art

[0002] A lithium metal battery has a different structure and principle from common battery technologies such as lithium ion batteries.

[0003] An electrode foil is an electrode with a positive charge. The electrode foil is mainly composed of a substance that has already been an electrode active material or an electrode foil material.

[0004] The electrode foil material needs to be a recyclable substance that can store and return by inserting lithium ions. The electrode foil material needs to be electroactive and capable of undergoing reactions that can accept and release lithium ions. These reactions can be determined by the chemical properties of the electrode material.

[0005] Korean Patent Application Publication No. 10-2022-0067385 discloses the manufacture of such a solid electrolyte. However, the related art is configured to manufacture an electrode foil active material by coating a solid electrolyte, but there are problems in ensuring uniformity and coating flatness. Summary of the Invention

[0006] One aspect of the present disclosure aims to provide a pressing device for an electrode foil for a lithium metal secondary battery, thereby solving the problems of the conventional electrode manufacturing device that cannot ensure uniformity and coating flatness.

[0007] Provided is a pressing device for an electrode foil for a lithium metal secondary battery, the device including: a base metal transfer unit configured to transfer a base metal foil to a pressing space; a first transfer unit configured to transfer a first lithium metal foil to the pressing space; a second transfer unit configured to transfer a second lithium metal foil to the pressing space; a hard roller disposed on one side of the pressing space; and an elastic roller disposed on the other side of the pressing space, wherein the hard roller and the elastic roller can press the base metal foil, the first lithium metal foil, and the second lithium metal foil.

[0008] The elastic roller may include a roller core and a coating unit provided on an outer circumferential surface of the roller core.

[0009] In addition, it may further include a pressing drive unit configured to press the elastic roller toward the hard roller.

[0010] It may further include an encoder configured to measure the rotation of the hard roller.

[0011] It may further include a rotation drive unit configured to rotate the elastic roller.

[0012] In addition, the hard roller can be configured to rotate freely.

[0013] The base metal transfer unit may include: a first sensor unit configured to measure the moving speed of the base metal foil; and a controller configured to control the rotation drive unit based on the value received from the first sensor unit.

[0014] In addition, the controller can be configured to control the rotation drive unit based on the value received from the first sensor unit and the value received from the encoder.

[0015] It may further include a reinforcing lamination module configured to cut the first lithium metal foil transferred from the first transfer unit and the second lithium metal foil transferred from the second transfer unit and tack laminate the end reinforcing layers of the advancing lithium metal foils to both surfaces of the base metal foil.

[0016] The reinforcing lamination module may be composed of a pair, the reinforcing lamination modules are symmetric left and right, and the reinforcing lamination module includes reciprocating blades respectively.

[0017] In addition, the reinforcing lamination module can be configured to cut the first lithium metal foil and the second lithium metal foil to a specified length.

[0018] The reinforcing lamination module can be controlled to tack laminate the front ends of the advancing first lithium metal foil and the advancing second lithium metal foil at a specified distance from the rear ends of the previous first lithium metal foil and second lithium metal foil.

[0019] The pressing device for the electrode foil of the lithium metal secondary battery according to the embodiment of the present disclosure can improve the uniformity and coating flatness of the electrode assembly.

[0020] The present invention can be used not only for the production of lithium metal batteries but also for the manufacture of solid-state batteries. Description of the Drawings

[0021] Figure 1 is a perspective view of an electrode foil manufactured according to an embodiment of the present disclosure.

[0022] Figure 2 is a front view of a manufacturing device for a secondary battery provided with a pressing device for an electrode foil of a lithium metal secondary battery according to an embodiment of the present disclosure.

[0023] Figure 3 is a perspective view of a pressing device according to an embodiment of the present disclosure.

[0024] Figure 4 is an exploded perspective view of a pressing device according to an embodiment of the present disclosure.

[0025] Figure 5is a conceptual diagram illustrating operations of an elastic roller and a hard roller in a lamination apparatus of an electrode foil of a lithium metal secondary battery according to an embodiment of the present disclosure.

[0026] Figure 6 is a conceptual diagram illustrating deformation of an elastic roller in an embodiment of the present disclosure.

[0027] Figure 7 is a conceptual diagram showing the speeds of the foil, the elastic roller, and the hard roller in the pressing area in the embodiment of the present disclosure.

[0028] Figure 8A , Figure 8B , Figure 8C , Figure 8D , Figure 8E , Figure 8F , Figure 8G , Figure 8H and Figure 8I FIG. 4 is a diagram showing an operating state of a pressing device for pressing an electrode foil of a lithium metal secondary battery according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] Hereinafter, the pressing device of the electrode foil of the lithium metal secondary battery according to the embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, in the following description of the embodiment, the constituent elements may be named differently in the relevant field. However, if the constituent elements have functional similarity and identity, they may be considered to be equivalent configurations despite the adoption of modified embodiments. In addition, the reference numerals assigned to the respective constituent elements are written for ease of description. However, the contents described in the drawings in which the reference numerals are written do not limit the respective constituent elements to the scope in the drawings. Similarly, although the configuration in the drawings adopts a partially modified embodiment, if the constituent elements have functional similarity and identity, they may be considered to be equivalent configurations. In addition, in view of the level of a person with ordinary skills in the relevant technical field, if the constituent element is considered to be a constituent element that needs to be naturally included, the description of the constituent element is omitted.

[0030] Figure 1 is a perspective view of an electrode foil manufactured according to an embodiment of the present disclosure.

[0031] Reference Figure 1, the electrode foil manufactured according to an embodiment of the present disclosure may have a lithium metal foil cut to a predetermined length and attached to a base metal foil 20. The lithium metal foil may be attached to both surfaces of the base metal foil 20 and may be symmetrically attached around the base metal foil 20. The lithium metal foils may be continuously provided at a predetermined interval d in the length direction of the base metal foil 20. The electrode foil (hereinafter referred to as "electrode assembly 10") manufactured in the electrode foil manufacturing apparatus according to an embodiment of the present disclosure may be used after being cut to a predetermined size in a separate apparatus for manufacturing a lithium metal secondary battery. In other words, the manufacturing apparatus of the electrode foil of the lithium metal secondary battery according to an embodiment of the present disclosure may continuously manufacture the electrode foil as a previous stage in the manufacture of the lithium metal secondary battery.

[0032] In an embodiment of the present disclosure, the base metal foil 20 is an electrode foil of a lithium metal secondary battery and may be composed of various metal elements and, by way of example, may be composed of copper (Cu). Additionally, the lithium metal foil 30 may be composed of lithium (Li) and may be composed of a mixture of various elements to improve the performance of the lithium metal secondary battery.

[0033] Figure 2 is a front view of a manufacturing apparatus 1 of a secondary battery provided with a pressing device 1000 for an electrode foil of a lithium metal secondary battery according to an embodiment of the present disclosure.

[0034] The pressing device 1000 for an electrode foil of a lithium metal secondary battery according to an embodiment of the present disclosure may be provided in a manufacturing apparatus for an electrode foil of a lithium metal secondary battery.

[0035] First, reference will be made to Figure 2 describe the overall configuration of the manufacturing apparatus 1 for an electrode foil of a secondary battery.

[0036] In an embodiment of the present disclosure, the manufacturing apparatus for an electrode foil of a lithium metal secondary battery may be divided according to an object (dashed line) to be supplied or recovered. The manufacturing apparatus for an electrode foil of a lithium metal secondary battery may include: a base metal foil supply unit 200 provided on a main frame 100 formed with a predetermined area in the vertical direction; a first lithium metal foil supply unit 300; a second lithium metal foil supply unit 400; a first film supply unit 600; a second film supply unit 700; a third film supply unit 800; a pressing device 1000; and an electrode foil winding unit 500.

[0037] The base metal foil supply unit 200 is configured to supply the base metal foil 20.

[0038] The lithium metal foil supply units 300 and 400 are provided in a pair and are configured to supply the lithium metal foils 30 or 40 attached to both surfaces of the base metal foil 20.

[0039] The first film supply unit 600 and the second film supply unit 700 are configured to supply a first film 51 and a second film 52 to a lamination device 1000, which will be described later. The first film and the second film are provided to prevent the foil from sticking to the surface of the roller when it is laminated by the roller and to ensure uniform lamination quality.

[0040] The lamination device 1000 is configured to attach a first lithium metal foil 30 and a second lithium metal foil 40 of a predetermined length to two surfaces of a base metal foil 20 in a lamination space. Here, the lamination space refers to a space where the metal foils are supplied, cut, and attached to each other. The lamination device 1000 is configured to cut the lithium metal foils 30 and 40 at a predetermined interval and continuously attach the lithium metal foils 30 and 40 to the base metal foil 20.

[0041] The third film supply unit 800 is configured to supply a third film 53 that can protect the electrode assembly 10 wound in the electrode foil winding unit 500.

[0042] The electrode foil winding unit 500 is configured to wind the electrode assembly 10 manufactured in the lamination device 1000.

[0043] Hereinafter, Figures 3 to 8I a lamination device for an electrode foil of a lithium metal secondary battery according to an embodiment of the present disclosure will be described in detail.

[0044] Below will be based on Figure 2 the layout shown in to describe the above configuration, but the positions of the respective structures are not limited. In other words, each element can be deformed and arranged at various positions on the main frame 100 extending in the vertical direction.

[0045] Figure 3 is a perspective view of a lamination device 1000 according to an embodiment of the present disclosure. Figure 4 is an exploded perspective view of a lamination device 1000 according to an embodiment of the present disclosure.

[0046] Referring to Figure 3 and Figure 4 , in this embodiment, the lamination device 1000 is configured to symmetrically attach a lithium metal foil of a predetermined length to both sides of the base metal foil 20.

[0047] The lamination device 1000 may include a base metal foil transfer unit 1100, a first transfer unit 1200, a second transfer unit 1300, a reinforcement lamination module 1400, a mold unit 1430, a main lamination pressing unit 1500, and a controller (not shown).

[0048] The base metal foil transfer unit 1100 is configured to transfer the base metal foil transferred from the base metal foil supply unit to the lamination space at an appropriate speed. The base metal foil transfer unit 1100 may include a first sensor unit 1110 configured to measure the linear velocity of the base metal foil.

[0049] The first transfer unit 1200 is configured to transfer the first lithium metal foil 30 to the lamination space. The second transfer unit 1300 is configured to transfer the second lithium metal foil 40 to the lamination space.

[0050] The first transfer unit 1200 and the second transfer unit 1300 may respectively include dancers, drive rollers 1220 and 1320, and sensor units 1210 and 1310. The dancers are configured to keep the tension of the transferred lithium metal foils 30 and 40 at a constant level.

[0051] The first drive roller 1220 and the second drive roller 1320 are configured to supply the lithium metal foils 30 and 40 at the same linear velocity when attached to the base metal foil 20. A drive motor (not shown) may be connected to each of the drive rollers 1220 and 1320, and the linear velocity of the lithium metal foils 30 and 40 may be adjusted according to the drive of the motor.

[0052] The second sensor unit 1210 and the third sensor unit 1310 are configured to measure the speed at which the lithium metal foil moves. However, although not shown, the first transfer unit 1200 and the second transfer unit 1300 may be configured to include a position adjustment unit to prevent misalignment and align the position of the supplied lithium metal foil, and may be configured to include at least one idle roller 1101 configured to transfer the foil along a desired path.

[0053] The reinforcement lamination module 1400 consists of a pair. Each of the reinforcement lamination modules 1400 cuts each of the lithium metal foils and is configured to attach the front end of the cut lithium metal foil to the base metal foil 20. The reinforcement lamination module 1400 is configured to attach (in other words, weld) the ends of the foils. Here, "attach" means keeping the foils in a mutually laminated state without applying external force.

[0054] Here, the term "front end" refers to the end of the lithium metal foil facing the main lamination pressing unit when the lithium metal foil is cut by the reinforcement lamination module 1400. In other words, the term "front end" refers to the front end in the direction towards which the lithium metal foil is oriented.

[0055] The reinforcement lamination module 1400 may include a first reinforcement lamination module 1410 and a second reinforcement lamination module 1420 which are symmetrically arranged left and right.

[0056] The first reinforcement lamination module 1410 may include a first pushing block 1411 and a first reinforcement lamination driving unit 1413.

[0057] The first pushing block 1411 is configured to adsorb the first lithium metal foil with its end and cut the first lithium metal foil with the corner of the end. The first pushing block 1411 may be provided with a first adsorption unit at its end. The first adsorption unit 1414 may include a plurality of adsorption holes and is configured to receive negative pressure from the outside and adsorb the first lithium metal foil 30 in close contact with the end. A first cutter 1412 may be provided at the lower corner of the end of the first pushing block 1411. The first cutter 1412 may be provided by cutting the corner of the pushing block at a specified angle to serve as a cutter, or may be provided as a separate blade and coupled to the end of the first pushing block 1411.

[0058] The first pushing block 1411 may be configured to have a width larger than the width of the first lithium metal foil and is configured to stably adsorb or cut the first lithium metal foil. The first pushing block 1411 is configured to reciprocate horizontally on the frame of the first reinforcement lamination module 1410.

[0059] The first reinforcement driving unit 1413 may be configured to move the first pushing block 1411 horizontally in a reciprocating manner. The amount of movement of the first reinforcement driving unit 1413 may be controlled by a controller.

[0060] Similar to the first reinforcement lamination module 1410, the second reinforcement lamination module 1420 may include a second reinforcement lamination driving unit 1423, a second pushing block 1421, a second cutter 1422, and a second adsorption unit 1424. The second reinforcement lamination module 1420 may be provided to be spaced apart from the first reinforcement lamination module 1410 by a specified distance in the horizontal direction on the attachment area.

[0061] The first reinforcement lamination module 1410 and the second reinforcement lamination module 1420 are moved by their respective driving units to horizontally position the ends of the first pushing block 1411 and the second pushing block 1421 in contact with each other, so that the lithium metal foil can be reinforced and laminated to the base metal foil 20.

[0062] The die unit 1430 is configured to jointly cut the lithium metal foils 30 and 40 with the first reinforcement lamination module 1410 and the second reinforcement lamination module 1420. The die unit 1430 moves to the cutting position when the lithium metal foils 30 and 40 are cut, and can move to the standby position to prevent interference with the reinforcement lamination modules 1410 and 1420 when the lithium metal foils 30 and 40 are being reinforced and laminated.

[0063] The die unit 1430 may be configured to include a die block 1431 and a linear guide 1432.

[0064] The pressing module 1431 can be configured to move vertically on the main frame 100. The pressing module 1431 can be connected to the main frame through a linear guide 1432. The pressing module driving unit 1433 can be driven to reciprocate the pressing module 1431 between a standby position and a cutting position.

[0065] Blade receiving grooves formed in the horizontal direction can be provided on both sides of the pressing module 1431 so that the first cutter 1412 and the second cutter 1422 of the reinforcing lamination module 1400 can be inserted. The pressing module 1431 can be composed of a pair arranged in the horizontal direction. The elastic unit 1512 can be provided between the pair of pressing modules 1431 and is configured to absorb shock when a force is applied in the lateral direction.

[0066] The pressing module 1431 can rise to a height at which there is no interference when the reinforcing lamination modules 1410 and 1420 reinforce the laminated metal foil at the standby position. Thereafter, the reinforcing lamination module 1400 can descend back to the cutting position when cutting the lithium metal foil after the reinforcing lamination is completed.

[0067] The main lamination pressing unit 1500 is configured to press and attach in the thickness direction the lithium metal foils 30 and 40 and the base metal foil 20 whose front ends are reinforced and laminated by a pair of reinforcing lamination modules 1410 and 1420. The base metal foil 20 and the lithium metal foils 30 and 40 that have passed through the main lamination pressing unit 1500 are completely attached to each other. In other words, the main lamination pressing unit 1500 can achieve pressure-activated lamination of the foils.

[0068] The main lamination pressing unit 1500 can include a hard roller 1520, an elastic roller 1510, and a rotary drive unit 1530.

[0069] The hard roller 1520 has a columnar or cylindrical shape and can have a hard outer surface. The hard roller 1520 is a free-rotating roller and can be configured to rotate freely by an external force. The rotation center axis of the hard roller 1520 can be fixed to the main frame. In other words, the hard roller 1520 is configured to rotate while its center axis is fixed.

[0070] The elastic roller 1510 is configured to press the foil while reducing the gap with the hard roller 1520 to form an electrode assembly. The outer peripheral surface of the elastic roller 1510 can be coated with an elastic material.

[0071] As an example, the elastic roller 1510 can be configured to move toward the hard roller 1520 by the pressure driving unit 1540. The pressure driving unit 1540 applies an appropriate force through a controller described later and transfers it to the elastic roller 1510. In addition, the elastic roller 1510 is connected to the rotational driving unit 1530 and is configured to receive a rotational force. When the rotational driving unit 1530 rotates while the elastic roller 1510 and the hard roller 1520 tightly press the foil, the hard roller 1520 also rotates.

[0072] In an embodiment of the present disclosure, the main lamination pressing unit 1500 is asymmetrically arranged for the following reasons.

[0073] First, when a pair of elastic rollers 1510 are provided in the main lamination pressing unit 1500, stress concentrates in a part of each elastic roller 1510 and deforms unevenly, and an uneven force is transferred to the pressed foil. As a result, a large number of horizontal wrinkles and cracks appear in the electrode assembly.

[0074] Second, when a pair of hard rollers 1520 are provided in the main lamination pressing unit 1500, the stress generated during the lamination process may not be distributed, and the electrode assembly loses uniformity due to bubbles or the like.

[0075] Third, even when an elastic roller 1510 and a hard roller 1520 are provided, when the hard roller 1520 is actively driven, the stress on the lithium metal foil in contact with the hard roller 1520 rapidly increases, causing deformation. As a result, horizontal wrinkles or cracks appear, and in severe cases, the lithium metal foil may rupture.

[0076] Therefore, the uniformity of the electrode assembly can be improved by actively rotating and attaching the elastic roller 1510 that undergoes appropriate deformation to appropriately press and attach the foil.

[0077] A controller (not shown) controls the driving element based on information received from the first sensor unit 1110, the second sensor unit 1210, the third sensor unit 1310, and the encoder 1521. In an embodiment of the present disclosure, the controller can appropriately control the rotational driving unit 1530 based on information received particularly from the first sensor unit 1110 and the encoder 1521.

[0078] In addition, the controller can adjust the rotational speeds of the first driving motor and the second driving roller 1320 based on the linear velocity information of each of the lithium metal foils. The controller can control the reinforcement lamination module 1400 to periodically cut and reinforce the laminated lithium metal foils 30 and 40.

[0079] The controller can reduce the speeds of the driving rollers 1220 and 1320 or stop the supply for a specified time to complete the cutting of the lithium metal foil and form a gap d in the transport direction in the electrode assembly. In this regard, the buffer and the floating roller can operate to maintain the operation of the lithium metal foil supply unit.

[0080] Figure 5 is a conceptual diagram showing the operations of the elastic roller 1510 and the hard roller 1520 in the electrode foil laminating device 1000 of a lithium metal secondary battery according to an embodiment of the present disclosure.

[0081] The elastic roller 1510 presses the first lithium metal foil 30, the base metal foil 20, and the second lithium metal foil 40 in the thickness direction through the pressure driving unit 1540, and the second lithium metal foil is supported by the hard roller 1520. As the elastic roller 1510 presses the foils in the thickness direction, the foils are attached to each other. In this regard, the foils move according to the frictional force in the contact area of the elastic roller 1510, and the hard roller 1520 also rotates as the foils move. In other words, the hard roller 1520 rotates passively, and the elastic roller 1510 rotates actively.

[0082] Figure 6 is a conceptual diagram showing a deformation of the elastic roller 1510 in an embodiment of the present disclosure.

[0083] A cylinder or a cylindrical roller core 1511 may be provided at the center of the elastic roller 1510. The elastic roller 1510 may be provided with an elastic unit 1512 having a specified thickness along the outer circumferential surface of the roller core 1511. The elastic unit 1512 is made of a material having a certain amount of elasticity and may be configured to deform a certain amount according to an external force. For example, the elastic unit 1512 may be made of a rubber-based material or a polymer-based material.

[0084] The elastic roller 1510 and the hard roller 1520 may be configured to have similar outer diameters when there is no external force. However, the hard roller 1520 may be configured to have a curvature corresponding to the curvature of the elastic roller 1510 that changes when pressed. In this regard, the hard roller 1520 may have a larger outer diameter than the elastic roller 1510.

[0085] Figure 7 is a conceptual diagram showing the speeds of the foils, the elastic roller 1510, and the hard roller in the pressing area in an embodiment of the present disclosure.

[0086] The hard roller 1520 is provided with an encoder 1521 to obtain information related to rotation. When the roller moves, the linear velocity on the side surface is proportional to the angular velocity, but in the case of the elastic roller 1510, due to deformation, the linear velocity on the surface is not proportional to the angular velocity. Therefore, in order to accurately measure the linear velocity at the main lamination part, information is collected from the hard roller 1520 whose outer diameter does not change and the relationship between the speed and the angular velocity is maintained.

[0087] The controller can control the transfer speed of the lithium metal foil in the first transfer unit 1200 and the second transfer unit 1300 based on the linear speed V1 of the base metal foil. In addition, the controller can control the rotation drive unit 1530 based on the linear speed of the base metal foil. The rotation drive unit 1530 is composed of a servo motor and is configured to follow the input. In this regard, since the hard roller 1520 ultimately rotates through the rotation drive unit 1530, the controller calculates the linear speed on the outer peripheral surface of the hard roller based on the angular velocity obtained from the encoder 1521. The controller feedback-controls the rotation drive unit 1530 so that the linear speed on the outer peripheral surface of the hard roller 1520 becomes the same as the linear speed of the base metal foil. In other words, even when an accurate linear speed may not be measured / calculated on the deformed outer peripheral surface of the elastic roller 1510, the linear speed of the outer peripheral surface can be measured / calculated by the rotatable hard roller 1520 that can be corrected.

[0088] Since the linear speed of the foil supplied under the control of the controller and the linear speed at the lamination part remain the same, a uniformly laminated electrode assembly can be manufactured.

[0089] Hereinafter, reference will be made to Figures 8A to 8I Describe the operation of the lamination device 1000 according to this variant. The following operations can be controlled by the controller. For ease of explanation, the point attached to the rear end of the previous lithium metal foil is represented by a square symbol, and the point attached to the front end of the previous lithium metal foil is represented by a circular symbol.

[0090] Figures 8A to 8I is a conceptual diagram showing the operation of the lamination device 1000 according to this variant.

[0091] First, with reference to Figure 8A , the first lithium metal foil 30, the base metal foil 20, and the second lithium metal foil 40 are continuously supplied to the elastic roller 1510 and the hard roller 1520 in a state where they are reinforced and laminated on their front sides. The metal foils can be attached while passing through the elastic roller 1510 and the hard roller 1520. In the lamination process described below, the first film 51 can continuously pass through the outer peripheral surface of the elastic roller 1510, and the second film 52 can continuously pass through the outer peripheral surface of the hard roller 1520.

[0092] In this regard, the first reinforced lamination module 1410, the second reinforced lamination module 1420, and the lamination module 1431 can wait at the standby position.

[0093] With reference to Figure 8B , the lamination module 1431 descends to the cutting position without interfering with the transfer of the base metal foil. In this regard, the height of the lamination module 1431 can be aligned to the position where the first cutter 1412 and the second cutter 1422 can be inserted into the blade receiving groove.

[0094] Referring to Figure 8C , the first pressing block 1411 and the second pressing block 1421 move toward each other and are in close contact with both sides of the pressing module 1431. In this regard, the adsorption units 1414 and 1424 of the first pressing block 1411 and the second pressing block 1421 operate to adsorb and fix the first lithium metal foil 30 and the second lithium metal foil 40. Even when the first pressing block 1411 and the second pressing block 1421 excessively press the pressing module 1431, the pressing module 1431 can retract a certain distance, thereby preventing damage to the lithium metal foils 30 and 40.

[0095] Referring to Figure 8D , the cutter driving unit is then driven to move the first cutter 1412 and the second cutter 1422 forward. The first lithium metal foil 30 and the second lithium metal foil 40 are cut by moving the first cutter 1412 and the second cutter 1422.

[0096] Figures 8B to 8D The operation of [] can be quickly executed. When such a cutting operation is performed on the lithium metal foil, the rotation of the elastic roller 1510 can be maintained.

[0097] Referring to Figure 8E , the first pressing block 1411 and the second pressing block 1421 then return to their original positions. In this regard, the front end of the advancing first lithium metal foil 32 remains fixed to the adsorption portion 1414 of the first pressing block 1411. Similarly, the front end of the advancing second lithium metal foil 44 remains fixed to the adsorption portion 1424 of the second pressing block 1421. In this state, the rear ends of the leading first lithium metal foil 31 and the leading second lithium metal foil 41 can maintain their postures by their own strength and are continuously pulled between the hard roller 1520 and the elastic roller 1510.

[0098] Referring to Figure 8F , a preparatory operation for reinforcing and laminating the metal foils 32 and 42 is then performed. The pressing module 1431 can rise to a standby position where the pressing blocks 1411 and 1421 do not contact during horizontal movement. At the same time, the elastic roller 1510 and the hard roller 1520 operate to perform main lamination on a certain area of the leading lithium metal foils 31 and 41. In this regard, the base metal foil 20 is also supplied to the main lamination pressing unit 1500 while maintaining the linear velocity.

[0099] Referring to Figure 8GWhen the rear ends of the preceding lithium metal foils 31 and 41 are spaced apart from the front ends of the advancing lithium metal foils 32 and 42 by a preset length, the advancing lithium metal foils 32 and 42 and the base metal foil 20 are reinforced and laminated (see a1 and a2). In this regard, the first lithium metal foil 32 fixed by the first pressing block 1411 and the second lithium metal foil 44 fixed by the second pressing block 1421 are in close contact with the base metal foil 20 and are pressed to form a reinforced laminate.

[0100] Referring to Figure 8H , the first pressing block 1411 and the second pressing block 1421 then retract and return to their original positions.

[0101] Thereafter, referring to Figure 8I , the first driving roller and the second driving roller operate to perform main lamination on the advancing lithium metal foils 32 and 42 such that the linear velocity of the lithium metal foils is adjusted to be equal to the supply linear velocity of the base metal foil.

[0102] Referring to the above Figures 8A to 8I , the described stages can be repeatedly executed when generating each unit electrode assembly.

[0103] As described above, the pressing device for the electrode foil of the lithium metal secondary battery according to the embodiment of the present disclosure can accurately adjust the supply speed and rolling speed while preventing damage to the metal foil, thereby improving the uniformity and coating flatness of the electrode foil.

Claims

1. A pressing device for an electrode foil of a lithium metal secondary battery, the device comprising: A base metal transfer unit configured to transfer a base metal foil to a pressing space; A first transfer unit configured to transfer a first lithium metal foil to the pressing space; A second transfer unit configured to transfer a second lithium metal foil to the pressing space; A hard roller provided on one side of the pressing space; And An elastic roller provided on the other side of the pressing space, Wherein the hard roller and the elastic roller press the base metal foil, the first lithium metal foil, and the second lithium metal foil.

2. The apparatus according to claim 1, wherein The elastic roller includes a roller core and a coating unit provided on an outer peripheral surface of the roller core.

3. The device according to claim 2, further comprising a pressing drive unit configured to press the elastic roller toward the hard roller.

4. The device according to claim 3, further comprising an encoder configured to measure the rotation of the hard roller.

5. The device according to claim 4, further comprising a rotation drive unit configured to rotate the elastic roller.

6. The apparatus according to claim 5, wherein The hard roller is configured to rotate freely.

7. The apparatus according to claim 6, wherein The base metal transfer unit includes: A first sensor unit configured to measure a moving speed of the base metal foil; and A controller configured to control the rotation drive unit based on a value received from the first sensor unit.

8. The apparatus according to claim 7, wherein, The controller is configured to control the rotation drive unit based on a value received from the first sensor unit and a value received from the encoder.

9. The device according to claim 8, further comprising a reinforcement laminating module configured to cut the first lithium metal foil transferred from the first transfer unit and the second lithium metal foil transferred from the second transfer unit, and reinforce and laminate ends of the advancing lithium metal foils to two surfaces of the base metal foil.

10. The apparatus according to claim 9, wherein The reinforcement laminating module consists of a pair, the reinforcement laminating module is symmetric left and right, and the reinforcement laminating module includes blades that can reciprocate respectively.

11. The apparatus according to claim 10, wherein, The reinforcement laminating module is configured to cut the first lithium metal foil and the second lithium metal foil to a specified length.

12. The device according to claim 11, wherein, The reinforcement laminating module is controlled to reinforce and laminate the front ends of the advancing first lithium metal foil and the advancing second lithium metal foil at a specified distance from the rear ends of the preceding first lithium metal foil and second lithium metal foil.

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