Device for notching a secondary battery manufactured using the same

Abstract

Disclosed is a device for notching, at an interval of a unit electrode, a continuous electrode sheet in which an electrode active material is applied to one or both surfaces thereof, to form a plurality of unit electrodes from the electrode sheet, the device including a press to press notches on the top and the bottom of the electrode sheet at a set position, and two or more grippers arranged at the rear of the press based on a feed direction of the electrode sheet, the grippers drawing and transporting the electrode sheet by one pitch, a size corresponding to the unit electrode according to operation of the press, wherein while one of the grippers draws and transports the electrode sheet, the remaining grippers move to a position for drawing.

Claims

1. A device for notching, at an interval of a unit electrode, a continuous electrode sheet in which an electrode active material is applied to one or both surfaces thereof, to form a plurality of unit electrodes from the electrode sheet, the device comprising: a press to press notches on the top and the bottom of the electrode sheet at a set position; two or more grippers arranged at rear of the press based on a feed direction of the electrode sheet, the grippers drawing and transporting the electrode sheet by one pitch by turns, a size corresponding to the unit electrode according to operation of the press; and a tension portion arranged in front of the press based on the feed direction of the electrode sheet to apply back tension to the electrode sheet in a direction opposite to the transport direction of the gripper, wherein the grippers are disposed on an opposite side from the tension portion with respect to the press to allow the press to press notches while the electrode sheet is maintained under a tension between the grippers and the tension portion, wherein the grippers comprise a first gripper adjacent to the press and a second gripper arranged at the rear of the first gripper to alternately draw the electrode sheet such that the first gripper is located between the press and the second gripper in the feed direction, wherein, the grippers are moveable towards and away from the press such that, while one of the grippers draws and transports the electrode sheet away from the press, the remaining grippers move towards the press to a position for drawing, wherein each of the first gripper and second gripper includes an upper member disposed above the electrode sheet and a lower member disposed below the electrode sheet, wherein the upper member and the lower member of the first and second grippers are movable normal to the electrode sheet and parallel to the electrode sheet, and wherein the press presses notches between the top and the bottom of the electrode sheet such that the electrode sheet is divided into two or more line units parallel to the transport direction and two or more unit electrodes are formed at respective line units at one pitch.

2. The device according to claim 1, wherein, while the first gripper draws the electrode sheet from the press and transports the same, the second gripper returns to the position for drawing and starts to transport the electrode sheet from the press immediately after transport of the first gripper is finished.

3. The device according to claim 1, wherein the notches are formed on the top and the bottom of the electrode sheet, respectively, such that the notches are symmetrical to each other.

4. The device according to claim 1, wherein the press comprises a mold having at least two cavities to form a plurality of notches by one pressing operation.

5. The device according to claim 4, wherein the mold has four to six cavities.

6. The device according to claim 1, wherein the tension portion comprises a roller set to be rotatable and a motor axially connected to the roller, wherein the motor synchronizes with the gripper.

7. The device according to claim 1, wherein the tension portion comprises a roller to transport the electrode sheet, and a powder brake or a torque limiter to stop the roller.

8. The device according to claim 1, wherein an unwinder winding the electrode sheet and a meandering controller to control meandering of the electrode sheet are arranged at the front of the tension portion in this order.

9. The device according to claim 1, further comprising: an inspector to inspect the electrode sheet notched by the press at the rear of the gripper.

10. The device according to claim 1, wherein the electrode sheet comprises a tap.

11. The device according to claim 1, further comprising an apparatus to supply a protective material wound together with the pressed electrode sheet in order to protect the pressed electrode sheet.

12. The device according to claim 1, wherein the tension portion has a tension-maintaining module to apply back tension to the electrode sheet at the rear of the press in the direction opposite to the transport direction of the gripper, wherein the tension portion comprises a roller set to be rotatable and a motor axially connected to the roller, and wherein the motor synchronizes with the gripper, the motor being configured to stop operation at a point 5 to 10 mm in front of where the gripper stops so that the electrode sheet slips together with the roller to apply back tension to the electrode sheet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a partial schematic view illustrating a conventional notching device;

(3) FIG. 2 is a partial schematic view illustrating a notching device according to one embodiment of the present invention;

(4) FIG. 3 is a plane schematic view illustrating the electrode sheet of FIG. 2;

(5) FIG. 4 is a plane schematic view illustrating an electrode sheet according to another embodiment of the present invention;

(6) FIG. 5 is a schematic view illustrating a configuration of the notching device according to another embodiment of the present invention; and

(7) FIG. 6 is a schematic view illustrating a process of the notching device according to another embodiment of the present invention.

BEST MODE

(8) Now, the present invention will be described in more detail with reference to the following examples. These examples are provided only for illustrating the present invention and should not be construed as limiting the scope and spirit of the present invention.

(9) FIG. 2 is a partial schematic view of a notching device according to one embodiment of the present invention. FIG. 3 is a plane schematic view of the electrode sheet of FIG. 2.

(10) Referring to these drawings, a notching device 100a notches, at an interval of an unit electrode 16, a continuous electrode sheet 10 in which an electrode active material is applied to both surfaces thereof, to manufacture a plurality of unit electrodes 16 from the continuous electrode sheet 10.

(11) In addition, the notching device 100a includes a press 20a that presses respective notches 11 and 12 on the top and the bottom of the electrode sheet 10 at a set position, and a first gripper 30a and a second gripper 30b of a dual gripper structure that draw and transport the electrode sheet 10 by one pitch (p), a size corresponding to the unit electrode 16 according to the operation of the press 20a.

(12) The first gripper 30a and the second gripper 30b are arranged at the rear side of the press 20a based on the feed direction of the electrode sheet 10, and when the first gripper 30a draws and transports the electrode sheet 10, the second gripper 30b moves to the position for drawing.

(13) Specifically, while the first gripper 30a draws the electrode sheet 10 from the press 20a and transports the same to a position of B, the second gripper 30b returns to a position of C for drawing and transports the electrode sheet 10 from the press 20a consecutively from the position of B at which transport of the first gripper 30a is completed.

(14) The notches 11 and 12 are formed by the press 20a on the top and the bottom of the electrode sheet 10 such that they are symmetrical to each other.

(15) In addition, the press 20a includes a mold 22a, thus pressing the electrode sheet 10 to form notches 11 and 12, and only presses the electrode sheet 10 in a set state.

(16) Meanwhile, the press 20a synchronizes with the first gripper 30a and second gripper 30b. That is, while the press 20a stops, the first gripper 30a and the second gripper 30b draw the electrode sheet 10 by one pitch (p) and feed the electrode sheet 10 to the press 20a, and while the press 20a presses, operations thereof are stopped.

(17) In addition, the first gripper 30a and the second gripper 30b feed the electrode sheet 10 to the press by one pitch (p) by a drawing operation in a state of gripping the electrode sheet 10. The first gripper 30a and the second gripper 30b alternately operate. That is, while the first gripper 30a operates, moves from the position A to the position B and feeds the electrode sheet 10 by one pitch, the second gripper 30b returns from the position D to the position C (stand-by position) and is arranged so that it feeds the electrode sheet 10 successively (immediately) from the first gripper 30a.

(18) When the operation of first gripper 30a is finished, that is, when the first gripper 30a moves to the position B, completes feeding and the press 20a presses the notches, the second gripper 30b grips the electrode sheet 10 to prepare for feeding and, the second gripper 30b moves from the position C to the position D and successively feeds the electrode sheet 10 immediately after pressing via the press 20a is finished.

(19) Such a configuration in which two grippers 30a and 30b are used prevents intermittent feeding from occurring, as occurs when one gripper is used, while the gripper feeds the electrode sheet 10 and then returns to the original position, and thus further improves production efficiency.

(20) FIG. 4 is a plane schematic view illustrating an electrode sheet according to another embodiment of the present invention.

(21) Referring to FIG. 4 together with FIG. 2, the press 20a presses notches 13 and 14 between a first line and a second line, and two unit electrodes are divided into two line units at one pitch (p) in a movement direction of the electrode sheet 10a and two unit electrodes are notched at respective line units in one pitch (p).

(22) The press 20a includes a mold 22b having four pairs of cavities to form four taps 15 and notches 11, 12, 13 and 14 through a single pressing operation.

(23) In addition, the press 20a forms four taps 15 in the process of forming the notches 11, 12, 13 and 14 on the electrode sheet 10a. These taps 15 are formed in a region of the electrode sheet 10a to which an electrode active material is not applied and have a symmetrical structure at respective unit lines of the electrode sheet 10a.

(24) FIG. 5 is a schematic view illustrating a configuration of the notching device according to another embodiment of the present invention. FIG. 6 is a schematic view illustrating the process of FIG. 5.

(25) Referring to these drawings together with FIGS. 2 and 3, a notching device 200 includes an unwinder 50, a meandering controller 60, a tension portion 70, a press 20a that presses notches 11 and 12 on the top and the bottom of an electrode sheet 10, a first gripper 30a and a second gripper 30b that draw the electrode sheet 10 and transport the same to the press 20a, an inspector 80 and a rewinder 90.

(26) The tension portion 70 includes a tension-maintaining module 71 that applies back tension to the electrode sheet 10 at the front of the press 20a in a direction opposite to the transport direction of the first gripper 30a and the second gripper 30b and maintains predetermined tension of the electrode sheet 10.

(27) In addition, the meandering controller 60 that controls meandering of the electrode sheet 10 is arranged between the unwinder 50 that winds the electrode sheet 10 and the tension portion 70 that applies back tension to the electrode sheet 10, and an inspector 80 that inspects the electrode sheet 10 on which the notches 11 and 12 are pressed is arranged at the rear of the second gripper 30b.

(28) The rewinder 90 to rewind the inspected electrode sheet is arranged at the rear of the inspector 80, and the inspector 80 includes a camera 81 to obtain an image data from the notch-pressed electrode sheet and a decision module 82 to analyze the image data.

(29) Specifically, the electrode sheet 10 to be pressed is wound on the roller of the unwinder 50, the roll of the unwinder 50 is axially connected to a servo motor, and the electrode sheet 10 is thus actively unwound depending on a control signal applied to the servo motor.

(30) The meandering controller 60 prevents the electrode sheet 10 from meandering in the process of transporting the electrode sheet. A sensor (not shown) constituting the meandering controller 60 senses meandering of the electrode sheet 10 in the process of transporting the electrode sheet 10, thereby causing the first roll 61 and the second roll 62 constituting the meandering controller 60 to move in an axial direction and prevents the electrode sheet 10 from meandering. The electrode sheet 10 that is subjected to meandering control while passing through the meandering controller 60 is transported to the tension portion 70.

(31) The tension portion 70 controls tension of the electrode sheet 10 at the front of the press 20a and thereby prevents the electrode sheet 10 from meandering, and the electrode sheet 10 that passes through the tension portion 70 is transported to the press 20a through an idler roller 72.

(32) The press 20a presses a notch on the electrode sheet 10 according to the mold in a set position. Such an electrode sheet 10 is fed to the press 20a by a distance (p) between the notches 12 according to the operation of the first gripper 30a and the second gripper 30b and the distance is referred to as a pitch (p).

(33) The first gripper 30a and the second gripper 30b draw the electrode sheet 10 and transport the same to the press 20a by one pitch according to the pressing rate of the press 20a.

(34) The inspector 80 confirms whether pressing of the press 20a is within an acceptable error range through visual testing. The electrode sheet 10 passing through the inspector 80 is transported to the rewinder 90 and is wound on the roll 91.

(35) If necessary, another tension portion (not shown) may be arranged between the inspector 80 and the rewinder 90 so that the tension portion 70 maintains the tension of the electrode sheet 10 at the rear of the press 20a and thereby enables the electrode sheet 10 to maintain a tight state.

(36) In addition to these components, an apparatus to supply a protective material wound together with the pressed electrode sheet 10 may be added in order to protect the pressed electrode sheet 10 when the pressed electrode sheet 10 is wound on the roll of the rewinder 90.

(37) In addition, the electrode sheet 10 is transported to the tension portion 70 in a state that meandering of the electrode sheet 10 is controlled by the meandering controller 60.

(38) The press 20a presses the electrode sheet 10 at a set position, the first gripper 30a and the second gripper 30b draw the electrode sheet 10 at a high rate when pressing of the press 20a is finished, and feed the electrode sheet 10 to the press 20a again. Accordingly, the electrode sheet 10 jitters due to inertia since it rapidly moves and stops. This problem is solved by the tension portion 70.

(39) The tension portion 70 includes a tension-maintaining module 71 and back tension module (not shown), and the tension-maintaining module 71 applies predetermined tension to the electrode sheet 10 transported to the press at the front of the press. A weight dancer serving as the tension-maintaining module 71 is axially connected to a pneumatic cylinder (not shown) and includes a potential meter (not shown) to measure a movement angle of the weight dancer.

(40) The movement of the weight dancer 71 is measured by the potential meter and the unwinder 50 unwinds the material to a large or small extent (to a certain degree), based on the measured value and thereby maintains tension applied to the electrode sheet 10. More specifically, when the weight dancer 71 moves in a counterclockwise direction, the unwinder 50 increases a rotation rate of the servo motor, unwinds more material from the roll, and the weight dancer 71 is returned back by the force of the pneumatic cylinder and applies tension to the electrode sheet 10.

(41) When the weight dancer 71 moves in a clockwise direction, the unwinder 50 reduces a rate of rotation of the servo motor and thereby unwinds less material and the weight dancer 71 returns to the original position and reduces tension applied to the electrode sheet 10.

(42) As such, the weight dancer 71 synchronizes with the unwinder 50 and maintains predetermined tension of the electrode sheet 10 transported to the press 20a.

(43) The back tension module (not shown) prevents meandering of the electrode sheet 10 caused by instantaneous operation of the gripper 30a and the second gripper 30b. This back tension module is arranged at the front of the press 20a and preferably includes a servo roller.

(44) The servo roller is axially connected to the servo motor (not shown) and controls rotation of the servo roller using a control signal.

(45) Such a servo roller is set such that it moves synchronously with the first gripper 30a and the second gripper 30b. That is, when the first gripper 30a and the second gripper 30b operate, the servo motor rotates the servo roller in a forward direction, and when the operations of the first gripper 30a and the second gripper 30b are finished, the servo motor stops and the servo roller stops rotation. Preferably, the servo motor stops at a point 5 to 10 mm in front of where the first gripper 30a and the second gripper 30b stop and thereby prevents the servo roller from rotating by inertia after the first gripper 30a and the second gripper 30b stop. As such, before the first gripper 30a and the second gripper 30b stop operation, that is, before transport of the electrode sheet 10 to the press 20a is finished, the serve motors stop rotation of the servo roller and prevent further drawing of the electrode sheet 10 using friction generated by slip between the electrode sheet 10 and the servo roller. As a result, the electrode sheet 10 is further drawn by the first gripper 30a and the second gripper 30b and uttering of the electrode sheet 10 caused by inertia can be thus solved.

(46) The camera 81 may have any configuration so long as the configuration enables digital image data to be obtained, and preferably includes a camera using a charge-coupled device (CCD) with excellent image quality as an image sensor, and a decision module 82 decides whether or not pressing of the electrode sheet 10 is good according to an algorithm.

(47) The electrode sheet 10 subjected to a pitch test in the inspector 80 is fed to the rewinder 90 through the rollers and the pressed electrode sheet is wound on the rewinder 90.

(48) Meanwhile, a rear tension portion including a weight dancer and an air dancer to maintain tension of materials may further be present between the inspector 80 and the rewinder 90.

(49) In addition, the meandering controller may further be present between the inspector 80 and the rewinder 90. In this case, the meandering controller prevents the electrode sheet 10 from meandering when the pressed material is wound on the roll again.

(50) Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

INDUSTRIAL APPLICABILITY

(51) As apparent from the afore-going, the notching device according to the present invention stably forms notches on an electrode sheet at a high rate and thereby greatly improves production efficiency of the overall process.