Apparatus for simultaneously coating both sides of dry electrode material for secondary battery

Abstract

The apparatus for simultaneously coating both surfaces of a dry electrode material for a secondary battery of the present invention, configured as described above, can continuously form a dry electrode sheet having very uniform density and thickness through precise interval adjustment of a rolling roll, and is hardly affected by vibrations generated by motors during operations, thereby ensuring excellent operation precision.

Description

Double-sided simultaneous coating device for dry electrode materials for secondary batteries

[0001] The present invention relates to an electrode material coating device for a secondary battery, and more specifically, to a dry electrode material double-sided simultaneous coating device for a secondary battery that simultaneously coats electrode materials on both sides of a continuously transported current collector and has excellent coating precision as it is hardly affected by motor vibration during operation.

[0002] Unlike primary batteries, which are used once and then discarded, secondary batteries are rechargeable batteries that can be reused repeatedly and possess high output and excellent charge / discharge performance. Accordingly, they are being used importantly in various fields, ranging from mobile IT devices such as smartphones and laptop computers to power sources for electric vehicles and storage devices for storing electricity generated from wind or solar power.

[0003] A secondary battery has a basic composition of a positive electrode, a negative electrode, an electrolyte, and a separator. The positive electrode and the negative electrode are each manufactured into a secondary battery cell through an electrode process in which an active material, a conductive material, and a binder are dispersed or dissolved in a solvent to prepare a slurry, and the slurry is coated onto a current collector and then dried, followed by an assembly process and an activation process.

[0004] However, wet electrode manufacturing methods using solvents may result in defects such as pinholes or cracks during the drying process. Pinholes or cracks occur as the contained solvent evaporates. In addition, powder flotation occurs due to differences in the solvent evaporation rate, and powder flotation is a cause of degraded electrode quality.

[0005] To solve the aforementioned problems, a dry manufacturing method for producing electrodes without using a solvent is known. The dry manufacturing method is performed by passing an electrode material powder containing an active material, a binder, and a conductive material through a plurality of calender rolls. The electrode material powder that has passed through the calender rolls is laminated and fixed to a current collector as a dry electrode film having a certain thickness.

[0006] In this regard, Korean Published Patent Application No. 10-2022-0052852 (powder for electrodes for manufacturing a dry electrode for a secondary battery, a method for manufacturing the same, a method for manufacturing a dry electrode using the same, a dry electrode, a secondary battery including the same, an energy storage device, and a dry electrode manufacturing device) has been disclosed.

[0007] The present invention was created to resolve the above problems and aims to provide a double-sided simultaneous coating device for dry electrode materials for secondary batteries that can continuously form dry electrode sheets with very uniform density and thickness, and has excellent operational precision as it is hardly affected by vibrations generated from a motor during operation.

[0008] The double-sided simultaneous coating apparatus for a dry electrode material for a secondary battery according to the present invention, as a means of solving the problem to achieve the above objective, comprises: a frame having a plurality of guide rolls that guide the transport of a current collector; a rolling unit including a housing mounted on the frame and having a horizontally extended linear guide to pass a current collector to be coated through, a plurality of rolling rolls accommodated in parallel within the housing, a roll support block installed on the linear guide and rotatably supporting both ends of the rolling rolls, and a block pusher mounted between each roll support block and adjusting the spacing of the roll support blocks; a pusher drive unit that adjusts the spacing of the rolling rolls through the block pusher; a hopper that supplies electrode material powder between the end rolling rolls; and a rolling roll drive unit that rotates the rolling rolls at mutually different speeds so that the powder passes through the rolling rolls in sequence and is coated on the current collector.

[0009] In addition, a drive unit support structure that supports a rolling roll drive unit is spaced apart from the side of the above-mentioned rolling unit.

[0010] In addition, a horizontal linear guide is installed on the drive unit support structure, and the rolling roll drive unit is equipped with a motor supported by the linear guide and corresponding one-to-one with the rolling roller, and a coupling connecting the motor and the rolling roller.

[0011] In addition, the plurality of rolling rolls comprises a fixed roll fixed to the center of the unit housing, a plurality of movable rolls arranged in a row on opposite sides with the fixed roll in between, and a pair of receiving rolls located at the ends of both movable rolls and receiving electrode material powder from a hopper.

[0012] In addition, the rotational speeds of the receiving roll and the movable roll gradually increase toward the fixed roll side, and the rotational speed of the fixed roll is less than or equal to twice the rotational speed of the receiving roll at the end.

[0013] In addition, the diameter of the receiving roll is relatively smaller than the diameter of the movable roll.

[0014] In addition, the receiving roll is equipped with a first roll and a second roll spaced apart to allow electrode material powder to pass between them, the rotational speed of the second roll is relatively faster than the rotational speed of the first roll, and a plurality of grooves extending in the circumferential direction are formed on the outer surface of the second roll.

[0015] In addition, the block pusher is a hydraulic actuator that operates by hydraulic pressure provided from the outside, and the pusher drive unit comprises a hydraulic supply unit that outputs hydraulic pressure and a control valve that is connected to each block pusher and transmits hydraulic pressure to the block pusher.

[0016] In addition, a gap sensor for sensing the gap between the roll support blocks is further installed between the roll support blocks.

[0017] In addition, the motor is a water-cooled motor, and a cooling water supply unit that circulates cooling water to the motor is further provided.

[0018] In addition, each of the above rolling rolls is equipped with a roll heating unit for heating the rolling roll.

[0019] In addition, the roll heating unit includes a central heater installed inside the rolling roll and extended in the longitudinal direction, end heaters located at both ends of the central heater in the longitudinal direction, and a controller that independently drives the central heater and the end heaters.

[0020] The double-sided simultaneous coating device for a dry electrode material for a secondary battery according to the present invention, as described above, can continuously form a dry electrode sheet with very uniform density and thickness by precisely adjusting the gap of the rolling rolls, and has excellent operational precision as it is hardly affected by vibrations generated by the motor during operation.

[0021] FIG. 1 is a front view of a double-sided simultaneous coating apparatus for a dry electrode material for a secondary battery according to one embodiment of the present invention.

[0022] Figure 2 is a drawing showing the rear structure of the coating device illustrated in Figure 1.

[0023] FIG. 3 is a diagram illustrating the principle of motor vibration suppression in a coating device according to one embodiment of the present invention.

[0024] Figure 4 is a plan view showing the arrangement configuration of the rolling unit and the rolling roll drive unit.

[0025] Figure 5 is a drawing showing the rolling unit of Figure 1 separately.

[0026] Figure 6 is a diagram illustrating the coating of electrode material on a current collector in the rolling unit of Figure 5.

[0027] Figure 7 is a drawing illustrating a modified example of the receiving roll shown in Figure 6.

[0028] Figure 8 is a diagram illustrating the spreading principle of the electrode material formed through the receiving roll of Figure 7.

[0029] Figure 9 is a drawing illustrating the mounting structure of the trimming part of Figure 1.

[0030] Hereinafter, one embodiment according to the present invention will be described in more detail with reference to the attached drawings.

[0031] FIG. 1 is a front view of a double-sided simultaneous coating device (10) for a dry electrode material for a secondary battery according to one embodiment of the present invention, and FIG. 2 is a drawing showing the rear structure of the coating device shown in FIG. 1. As shown, the coating device (10) according to the present embodiment comprises a frame (11), a rolling unit (20), a pusher drive unit, a hopper (31), and a rolling roll drive unit.

[0032] The frame (11) is a support structure fixed on the ground and has a plurality of guide rolls (17). A current collector (101) provided from the outside passes through a rolling unit (20) while supported by the guide rolls (17), and is then wound onto an external electrode sheet winding roll (not shown). As the current collector (101) passes vertically downward through the rolling unit (20), it receives electrode material (103) on both sides. The result of coating electrode material (103) on both sides of the current collector (101) is an electrode sheet (100). The electrode material (103) is formed by rolling electrode material powder supplied through a hopper (31). The rolling unit (20) is mounted horizontally on the inside of the frame (11) and forms the electrode material powder to a certain width and thickness by rolling. The electrode material (103) formed in the rolling unit (20) is simultaneously coated on both sides of the electrode sheet (100) passing through the rolling unit (20).

[0033] FIG. 5 is a drawing showing the rolling unit of FIG. 1 separately, and FIG. 6 is a drawing showing the electrode material being coated on the current collector in the rolling unit. FIG. 7 is a drawing showing a modified example of the receiving roll shown in FIG. 6, and FIG. 8 is a drawing to explain the principle of spreading the electrode material formed through the receiving roll of FIG. 7.

[0034] As described above, the rolling roll unit (20) comprises a unit housing (21), a plurality of rolling rolls, a roll support block (22), a block pusher (23), and a gap sensor (23a). The unit housing (21) is a structure installed in the inner space of the frame (11) and is open vertically as shown in FIG. 3. The current collector (101) passes downward through the interior of the unit housing (21). Additionally, while the current collector (101) passes through the unit housing (21), electrode material (103) is coated on both sides of the current collector (101). The unit housing (21) is supported by a unit support structure (13) and maintains a horizontal position.

[0035] In addition, the unit housing (21) is equipped with a linear guide (13a). Two linear guides (13a) are extended in a straight line parallel to each other. The linear guides (13a) support the roll support block (22) so that it can slide. The roll support block (22) can slide while supported by the linear guides (13a).

[0036] The roll support block (22) is a block-shaped member that is positionally adjustable and supported on the linear guide (13a). Two roll support blocks (22) form a pair, and a rolling roll is placed between them. The rolling roll, while supported by the roll support block (22), can rotate by receiving rotational force from the rolling roll drive unit.

[0037] The rolling rolls are received in a mutually parallel manner inside the unit housing (21) and both ends are supported by the roll support blocks (22). The rolling rolls are arranged in parallel in the transverse direction and are spaced apart at intervals corresponding to the thickness of the electrode material to be manufactured. The spacing of the rolling rolls is adjusted by adjusting the spacing of the roll support blocks (22). As shown in FIG. 6, the rolling rolls consist of a fixed roll (27a), a movable roll (27b), and a receiving roll (26). The fixed roll (27a) is a rolling roll located in the center among the multiple rolling rolls. When there is an even number of rolling rolls, one of the two rolling rolls at the very center is the fixed roll (27a). Although the fixed roll (27a) is supported rotatably by the roll support blocks (22), it cannot move in the longitudinal direction of the linear guide. A fixing plate (25) for fixing the fixed roll (27a) is mounted on the unit housing (21).

[0038] The movable rolls (27b) are arranged in a line on opposite sides with the fixed rolls (27a) in between. In FIG. 6, five movable rolls (27b) are arranged on the left side of the drawing of the fixed rolls (27a) and four on the right side. The movable rolls (27b) rotate by receiving rotational force from the rolling roll drive unit.

[0039] The receiving roll (26) is a roller located at the end of both movable rolls (27b) and receives electrode material powder (P) from the hopper (31). The receiving roll (26) consists of a first roll (26a) and a second roll (26b). The electrode material powder is fed between the first roll (26a) and the second roll (26b), passes between the first roll (26a) and the second roll (26b), is rolled, and then moves toward the movable roll (27b) by adhering to the outer surface of the second roll (26b). The diameters of the first roll (26a) and the second roll (26b) are the same. Additionally, the diameters of the first and second rolls (26a, 26b) are smaller than the diameter of the movable roll (27b). The ratio of the diameters of the receiving roll (26) and the movable roll (27b) can be implemented differently depending on the embodiment.

[0040] In particular, the rotational speeds of the fixed roll (27a), movable roll (27b), second roll (26b), and first roll (26a) are all different. First, the rotational speed of the second roll (26b) is less than twice the rotational speed of the first roll (26a). Additionally, the rotational speed of the movable roll (27b) gradually increases as it moves from the end movable roll (27b) adjacent to the second roll (26b) toward the fixed roll (27a).

[0041] Among the multiple rolling rolls, the fastest rotating roll is a fixed roll (27a) and a movable roll (27b) adjacent to the fixed roll (27a) with the collector (101) in between. The fixed roll (27a) and the movable roll (27b) adjacent to the collector (101) rotate in opposite directions and have the same rotational speed. The rotational speed of the fixed roll (27a) is faster than twice the rotational speed of the first roll (26a). As the speeds of the rolling rolls differ as described above, the powder fed into both receiving rolls (26) can pass between the movable rolls (27b) and be coated on the collector (101). For reference, it is a known fact that a collector passing through two rollers rotating at different speeds is conveyed by adhering to the outer surface of the relatively faster roller.

[0042] The outer surfaces of the first roll (26a) and the second roll (26b) of the receiving hole (26) can both be formed smoothly. However, as shown in FIG. 7, a groove (26c) may be applied to the outer surface of the second roll (26b). The groove (26c) is a groove formed on the outer surface of the second roll (26b), has a certain width, and extends in the circumferential direction. When the second roll (26b) with the groove (26c) applied is used, a plurality of grooves (103a) remain on the cross-section of the electrode material (103) that has passed through the receiving hole (26), as shown in FIG. 8. The grooves (103a) are filled as the electrode material (103) passes through the rolling rolls in sequence, causing the electrode material (103) to spread more uniformly. If there is no groove (103a), the widthwise spreading of the electrode material (103) is unfavorable, and the density may become non-uniform.

[0043] Meanwhile, the block pusher (23) is a hydraulic actuator mounted between each roll support block (22) and adjusts the spacing between adjacent roll support blocks (22). Adjusting the spacing of the block support blocks (22) means adjusting the spacing of the rolling rolls. The reason for adjusting the spacing of the rolling rolls is to adjust the thickness of the final electrode material (103). The block pusher (23) is operated by a pusher drive unit. The pusher drive unit includes a hydraulic supply unit (37) and a plurality of control valves (24) as shown in FIG. 1. The hydraulic supply unit (37) is a unit including a hydraulic pump and a hydraulic fluid tank, is connected to the control valve (24), and transmits hydraulic pressure to the control valve (24).

[0044] The control valve (24) is a proportional control valve and is connected to each block pusher (23) and transmits hydraulic pressure to the block pusher (23). The block pusher (23) operates by the transmitted hydraulic pressure to adjust the spacing of adjacent roll support blocks (22). Each block pusher (23) can be controlled independently through the control valve (24).

[0045] In addition, a gap sensor (23a) is provided between each roll support block (22). The gap sensor (23a) senses the gap between adjacent roll support blocks (22) and transmits the sensing information to the pusher drive unit. The pusher drive unit can precisely control the gap of the roll support blocks (22) based on the gap data received from the gap sensor (23a).

[0046] FIG. 3 is a diagram illustrating the principle of motor vibration suppression in a coating device according to one embodiment of the present invention, and FIG. 4 is a plan view showing the arrangement configuration of a rolling unit and a rolling roll drive unit.

[0047] The above rolling roll drive unit acts to rotate each rolling roll (receiving hole, movable roll, fixed roll) at mutually different speeds so that powder passes through the rolling rolls in sequence and is coated on the collector (101). The rolling roll drive unit includes a motor (33) and a coupling (35). Additionally, the rolling roll drive unit is supported on the upper part of a drive unit support structure (15). The drive unit support structure (15) is a support structure spaced apart from the side of the rolling unit (20) and is equipped with a pair of linear guides (15a). The linear guides (15a) are parallel to the linear guides (13a) of the unit housing.

[0048] The drive unit support structure (15) supports the rolling roll drive unit. Since the drive unit support structure (15) is spaced apart from the rolling unit (20), vibrations generated in the rolling roll drive unit, that is, vibrations generated from the motor (33), are hardly transmitted to the rolling unit (20). The generated vibrations are transmitted to the ground through the drive unit support structure (15).

[0049] The rolling roll drive unit includes a motor (33) and a coupling (35). The motor (33) corresponds to each rolling roll in a one-to-one manner and is connected to the rolling roll through the coupling (35). The rotational force of the motor (33) is transmitted to the rolling roll through the coupling (35).

[0050] The motor (33) is supported by the linear guide (15a) and can move along the longitudinal direction of the linear guide (15a). For example, it moves together with the rolling roll when the block pusher (23) moves. The motor (33) is a water-cooled motor. As illustrated in enlarged view in FIG. 2, the motor (33) is provided with an inlet (33a) and an outlet (33b). The inlet (33a) is a port that receives cooling water delivered from the cooling water supply unit (39). The outlet (33b) is a hole through which cooling water that has completed heat exchange with the motor is discharged. The discharged cooling water is returned to the cooling water supply unit, cooled, and then circulated back to the motor (33).

[0051] Meanwhile, as shown in FIG. 3, a roll heating unit (28) is applied to each rolling roll. The roll heating unit (28) heats the rolling roll to enable more efficient rolling of the electrode material (103).

[0052] The roll heating unit (28) includes a central heater (28a), end heaters (28b), a heater driver (18c), and a controller (28d). The central heater (28a) is a linear heating element installed inside the rolling roll. The central heater (28a) intensively heats the central part of the outer surface of the rolling roll. Additionally, the end heaters (28b) are heating elements located at both ends in the longitudinal direction of the central heater (28a). The end heaters (28b) intensively heat the ends of the rolling roll. In this way, by applying the central heater (28a) and the end heaters (28b) separately, the heating temperature of the rolling roll can be partially controlled.

[0053] In addition, a temperature sensor (29) is placed inside the rolling roll. The temperature sensor (29) detects the heating temperature of the central heater and the end heater and transmits the detected information to the controller (28d).

[0054] The central heater (28a) and the end heater (28b) generate heat through power delivered via the heater driver (28c).

[0055] The controller (28d) controls the output temperature of the central heater (28a) and the end heater (28b) based on temperature information received from the temperature sensor (29). The control signal of the controller (28d) is transmitted to the heater driver (28c). The heater driver (28c) controls the temperature of the central heater and the end heater based on the received control signal.

[0056] FIG. 9 is a drawing illustrating the mounting structure of the trimming part (40) of FIG. 1.

[0057] Meanwhile, a pair of trimming units (40) are provided on the upper side of the central part of the rolling unit (20). The trimming units (40) cut the widthwise end of the electrode material (103) facing the current collector (101) so that the electrode material (103) has a certain width. Since the widthwise end of the electrode material that has moved through a number of rolling rolls takes on an irregular shape, it is trimmed using the trimming units. The trimming units (40) include a blade module (41). In addition, a disc-shaped rotating blade (41a) is provided at the lower end of the blade module (41). The rotating blade (41a) is a disc-shaped blade with a blade formed on the edge and cuts both widthwise ends of the electrode material (103) that moves in close contact with the outer surface of the rolling roll. The electrode material that has passed through the trimming units (40) is simultaneously stacked on both sides of the current collector (101) with a certain width.

[0058] Although the present invention has been described in detail through specific embodiments, the present invention is not limited to the above embodiments, and various modifications can be made by those skilled in the art within the scope of the technical concept of the present invention.

[0059] This invention relates to a secondary battery electrode material coating device that simultaneously coats electrode materials on both sides of a continuously transported current collector and ensures coating precision by preventing the influence of motor vibration, and is therefore industrially applicable.

Claims

1. A frame having a plurality of guide rollers that guide the transfer of the entire house; A rolling unit comprising: a housing mounted on the above frame and having a horizontally extended linear guide and passing a current collector to be coated through it; a plurality of rolling rolls accommodated in the housing in mutually parallel arrangement; a roll support block installed on the linear guide and rotatably supporting both ends of the rolling rolls; and a block pusher mounted between each roll support block and adjusting the spacing of the roll support blocks; A pusher drive unit that adjusts the gap of the rolling rolls through a block pusher; A hopper for supplying electrode material powder between the above-mentioned end rolling rolls; and A double-sided simultaneous coating device for a dry electrode material for a secondary battery, characterized by including a rolling roll drive unit that rotates the rolling rolls at mutually different speeds so that powder passes through the rolling rolls in sequence and is coated on the current collector.

2. In Paragraph 1, On the side of the above rolling unit, A double-sided simultaneous coating device for dry electrode materials for secondary batteries, characterized in that a drive unit support structure supporting a rolling roll drive unit is spaced apart.

3. In Paragraph 2, A horizontal linear guide is installed in the above drive unit support structure, and The above rolling roll drive unit is, A motor supported by a linear guide and corresponding one-to-one with a rolling roller, and A double-sided simultaneous coating device for dry electrode materials for secondary batteries, characterized by having a coupling connecting a motor and a rolling roller.

4. In Paragraph 1, The above plurality of rolling rolls are, A fixed roller fixed to the center of the unit housing, and A plurality of movable rolls arranged in a line on opposite sides with a fixed roll in between, and A double-sided simultaneous dry electrode material coating apparatus for a secondary battery, characterized by including a pair of receiving rolls located at the ends of both movable rolls and receiving electrode material powder from a hopper.

5. In Paragraph 4, A double-sided simultaneous coating apparatus for dry electrode materials for secondary batteries, characterized in that the rotational speeds of the receiving roll and the movable roll gradually increase toward the fixed roll side, and the rotational speed of the fixed roll is less than or equal to twice the rotational speed of the receiving roll at the end.

6. In Paragraph 4, A double-sided simultaneous coating apparatus for dry electrode materials for secondary batteries, characterized in that the diameter of the receiving roll is configured to be relatively smaller than the diameter of the movable roll.

7. In Paragraph 6, The above receiving roll is equipped with a first roll and a second roll spaced apart to allow electrode material powder to pass between them, and The rotational speed of the second roll is relatively faster than the rotational speed of the first roll, and A double-sided simultaneous coating apparatus for a dry electrode material for a secondary battery, characterized in that a plurality of grooves extending in the circumferential direction are formed on the outer surface of the second roll.

8. In Paragraph 1, The above block pusher is a hydraulic actuator operated by hydraulic pressure provided from the outside, and The pusher drive unit is, A hydraulic supply unit that outputs hydraulic pressure, and A double-sided simultaneous coating device for dry electrode materials for secondary batteries, characterized by having a control valve connected to each block pusher and transmitting hydraulic pressure to the block pusher.

9. In Paragraph 1, Between the above roll support blocks, A double-sided simultaneous coating device for dry electrode materials for secondary batteries, characterized by the additional installation of a gap sensor for sensing the gap of roll support blocks.

10. In Paragraph 3, The above motor is a water-cooled motor, and A double-sided simultaneous coating device for dry electrode materials for secondary batteries, characterized by further being equipped with a cooling water supply unit that circulates cooling water to the motor.

11. In Paragraph 1, A double-sided simultaneous coating device for dry electrode materials for secondary batteries, characterized in that each of the above-mentioned rolling rolls is equipped with a rolling heating unit for heating the rolling roll.

12. In Paragraph 11, The roll heating section is, A central heater installed inside the rolling roll and extended in the longitudinal direction, and End heaters located at both longitudinal ends of the central heater, and A double-sided simultaneous coating device for dry electrode materials for secondary batteries, characterized by including a controller that independently drives a central heater and an end heater.

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