Electrode forming device with slotted positioning pins and electrode forming method using the same

Abstract

The present invention relates to an electrode forming apparatus and an electrode forming method using the same, wherein the electrode forming apparatus has a slotted positioning pin configured to reduce a step that may occur during slotting of an electrode.

Description

Technical Field

[0001] This application claims the benefit of priority to Korean Patent Application No. 2020-0134693, filed on October 16, 2020, the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates to an electrode forming apparatus having a slotted positioning pin and an electrode forming method using the same. More specifically, the present invention relates to an electrode forming apparatus having a slotted positioning pin configured to reduce a step that may occur during slotting of an electrode and an electrode forming method using the same. Background Art

[0003] The secondary battery is manufactured by mounting an electrode assembly in a cylindrical or prismatic case made of a metal material or a pouch-shaped case made of a laminate sheet including aluminum, injecting an electrolyte into the case, and hermetically sealing the case.

[0004] Electrode assemblies having a structure in which positive electrodes and negative electrodes are stacked with a separator interposed therebetween are classified into: a jelly-roll type electrode assembly, configured to have a structure in which a long sheet type positive electrode coated with an active material and a long sheet type negative electrode coated with an active material are wound with a separator interposed therebetween; a stacked type electrode assembly, configured to have a structure in which a flat positive electrode and a flat negative electrode are stacked with a separator interposed therebetween; a stacked and folded type electrode assembly, configured to have a structure in which unit cells are wound in a state in which they are arranged on a long sheet type separator; or a laminated and stacked type electrode assembly, configured to have a structure in which unit cells are stacked with a separator interposed therebetween.

[0005] In the stacked type electrode assembly, the stacked and folded type electrode assembly, or the laminated and stacked type electrode assembly, a single-sided electrode plate or a double-sided electrode plate configured such that an electrode active material is applied to one surface or opposite surfaces of a current collector is used.

[0006] Generally, a method for manufacturing an electrode assembly includes a process for manufacturing an electrode sheet, a process for pressing the electrode sheet, a process for slitting the electrode sheet to a predetermined length to suit the standard of a battery, a vacuum drying process, a process for grooved electrode tabs on the electrode sheet, and a process for manufacturing an electrode assembly including the electrode sheet and a separator.

[0007] In connection with this, Figure 1 is a plan view showing a part of a conventional electrode manufacturing process.

[0008] Reference Figure 1The electrode material coated portion 120 is formed only on a portion of the electrode sheet 110 except the opposite side periphery 111 and the middle portion of the electrode sheet in the conveying direction A, and the electrode material uncoated portion 121 is formed on the remaining portion of the electrode sheet except the electrode material coated portion 120.

[0009] The electrode sheet 110 is divided into two equal parts along a longitudinal cutting line 112 at a middle portion of the electrode sheet 110 in the conveying direction A, namely, two unit electrode sheets 130 .

[0010] The first side periphery 114 of the unit electrode sheet 130 divided along the longitudinal cutting line 112 in the conveying direction A is grooved to form the electrode tab 113, and the second side periphery 115 of the unit electrode sheet is grooved to form a portion cut for manufacturing the unit electrode. Figure 1 In the embodiment, when the electrode sheet is divided into two equal parts along the longitudinal cutting line 112, the electrode tab 113 can be grooved at the same time.

[0011] In the specification of the present application, slotting includes not only the process of cutting the electrode tab into a suitable shape, but also the process of cutting the electrode tab into two equal parts along the longitudinal cutting line. In addition, the electrode tab includes a metal electrode tab with or without an electrode material coating portion.

[0012] In theory, when the electrode is slotted, the electrode sheet must be cut parallel to the conveying direction of the electrode sheet, and the electrode tab must be cut perpendicular to it, e.g. Figure 2 As shown in the upper part of FIG. In the electrode sheet 110, the thicknesses of the electrode material coated portion 120 and the electrode material uncoated portion 121 are different from each other. Therefore, when the notching is performed, the electrode tab is not cut correctly but is cut (notched) in a delayed state, i.e., a meander defect occurs (see FIG. Figure 2 ).

[0013] When steps are formed at the electrode tabs due to meander defects, 1) the upper and lower layers are not accurately aligned with each other during the stacking process of manufacturing the electrode assembly, thereby reducing the efficiency of the battery, 2) the protruding portions of the electrode tabs damage the diaphragm, and a short circuit may occur, and 3) when each electrode is rotated during the manufacture of the electrode assembly, the electrode position is precisely controlled and the standard of electrode stacking becomes blurred.

[0014] Patent document 1 discloses a method for manufacturing an electrode plate for a battery, using a punching machine composed of an upper press and a lower press capable of moving up and down, to continuously form a plurality of electrode plates from a belt-type or hook-type electrode plate by punching, wherein the upper press has a punch and a shear blade installed at the front thereof in a cutting direction, and the lower press has a die with a punching hole (in which the punch is inserted) and a shear blade installed at the front thereof in the cutting direction, and when punching is performed in a state where opposite sides of the electrode plate are adjacent to each other as a common side in the longitudinal direction of the electrode plate, assuming that one of the opposite sides in the direction of the electrode plates adjacent to each other is the opposite side A, and the common side is B, the angle formed by side A and side B is chamfered, and the lower press is configured so that a stepped upper portion is formed in the lower portion of the punching hole, the stepped upper portion having two or more steps, and the two or more steps have an increasing hole size along the punching direction.

[0015] Patent Document 1 does not disclose the structure of the slotting positioning pin according to the present invention, and does not propose a solution to the problem to be solved by the present invention, because the document is related to preventing clogging due to cuttings of the electrode plate and improving the service life of the slotting punch.

[0016] Patent document 2 discloses a slotting device for slotting a continuous electrode sheet so as to manufacture a plurality of unit electrodes from the electrode sheet, wherein the continuous electrode sheet has electrode active material applied to one surface or opposite surfaces thereof at intervals between unit electrodes, the slotting device comprising: a press configured to slot the upper and lower ends of the electrode sheet while the position of the press is fixed; and two or more clamps located at the rear of the press in the direction of supplying the electrode sheet, the clamps configured to hold and convey the electrode sheet at a spacing in response to the operation of the press, the spacing being a size corresponding to the unit electrode, wherein when one of the clamps holds and conveys the electrode sheet, the other clamps move to a holding position.

[0017] Patent Document 2 is characterized in that a cutout is formed in an electrode sheet, the electrode sheet is fed at a pitch by first and second grippers, and then the electrode sheet is punched to perform notching at predetermined intervals, however, it is not a solution to the meander defect.

[0018] Patent document 3 discloses an electrode manufacturing device including a grooved roller, which includes: a conveying unit configured to continuously convey a first electrode sheet so as to groove and cut the first electrode sheet, wherein the first electrode sheet has an electrode active material applied on a long sheet-type current collector; a grooved roller having a cylindrical structure, wherein the grooved roller is configured to groove one surface of the first electrode sheet by rotation to produce a continuously formed second electrode sheet having a one side periphery and another side periphery; and a cutter configured to cut the grooved second electrode sheet into a length corresponding to the width of the electrode so as to produce a final electrode, wherein the grooved roller includes a first grooved portion and a second grooved portion when viewed from above, the first grooved portion being configured to form a one side periphery of the second electrode sheet, and the second grooved portion being configured to form the other side periphery of the second electrode sheet.

[0019] Patent Document 3 describes the use of a grooved roll, whereby no groove step occurs. However, when a roll-type roll is used, the thickness deviation between the electrode material coated portion and the electrode material uncoated portion accumulates, which may increase the meandering defect, and Patent Document 3 does not recognize this problem.

[0020] Patent document 4 relates to a pressing device configured to form multiple electrode plates for a lithium-ion polymer battery for a hybrid electric vehicle at one time, wherein an upper press having a cutting device and a lower press configured to assist the upper press are installed, and a plurality of electrode plate components arranged in the battery are simultaneously formed by continuously supplying thin flat electrode plate materials therebetween, thereby enabling multiple electrode plates to be accurately, uniformly and continuously manufactured at one time.

[0021] In Patent Document 4, a grooved portion is formed on an intermediate cutter blade so that punching is performed while marking the boundary between electrode plate members; however, this document does not recognize the problem of meandering defects.

[0022] As described above, in the process of manufacturing a large number of electrodes by slotting, the problem of forming steps due to meandering defects has a lasting impact on the manufacture of electrode assemblies as subsequent processes and the performance of batteries based thereon. However, such a problem is still not recognized, and no clear solution to such a problem has been proposed.

[0023] Japanese Patent Publication No. 5159007 (December 21, 2012) (“Patent Document 1”)

[0024] Korean Patent Publication No. 1326628 (November 1, 2013) (“Patent Document 2”)

[0025] Korean Patent Publication No. 2026126 (September 23, 2019) (“Patent Document 3”)

[0026] Korean Patent Publication No. 1737790 (May 15, 2017) (“Patent Document 4”) Summary of the invention

[0027] Technical issues

[0028] The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrode forming apparatus and an electrode forming method using the electrode forming apparatus, which can solve the problem of step formation at an electrode tab that may occur during groove opening.

[0029] Technical Solution

[0030] In order to achieve the above-mentioned purpose, the present invention provides an electrode forming device, which includes: a sheet conveying unit, configured to move the electrode sheet at a predetermined speed; a fixing unit, configured to fix the electrode sheet; and a stamping unit, which is composed of a center stamping unit and a side stamping unit, and the center stamping unit and the side stamping unit are respectively configured to remove the center part of the electrode sheet and a part of the periphery of the electrode sheet by slotting, wherein the center stamping unit includes a hole stamping component and a slotted positioning pin.

[0031] The center punching unit may include: a rectangular body having a main axis along the moving direction of the electrode sheet; a hole punching member formed at the rear end of the rectangular body along the moving direction of the electrode sheet; and a slotted positioning pin formed below the front end of the rectangular body along the moving direction of the electrode sheet.

[0032] The cuboid body may be formed in a cuboid shape having a main axis along a moving direction of the electrode sheet, and may include a body punching surface configured as a lower surface of the cuboid body to punch the electrode sheet.

[0033] The hole stamping component may include: an expansion portion, extending from the rear end of the rectangular body along the moving direction of the electrode sheet, configured to increase the width of the main body stamping surface for stamping the electrode sheet at the expansion portion; a reduction portion, extending from the expansion portion, configured to reduce the width of the main body stamping surface for stamping the electrode sheet at the reduction portion along the main axis; and a pin stamping portion, extending from the reduction portion, configured to be a catching recess (catching recess) for stamping a slotted positioning pin in the electrode sheet.

[0034] The cross section of the slotted positioning pin can be any one of a circle, an arc, a wedge, a triangle and a quadrilateral.

[0035] The fixing unit may be provided with a middle groove in the middle of the fixing unit, and a shape of the middle groove corresponds to the center punching unit.

[0036] The intermediate groove may be formed to have a sufficient depth to allow the slotted positioning pin to be inserted therein.

[0037] In addition, the present invention provides an electrode forming method using the electrode forming device, and the electrode forming method includes the following steps: S1) using a sheet conveying unit to convey the electrode sheet to a predetermined length; S2) conveying the electrode sheet or the stamping unit so that the slotted positioning pins are captured in the recesses formed in the electrode sheet in the previous step of stamping; S3) using the stamping unit to press the electrode sheet to stamp the electrode sheet; and S4) separating the stamping unit from the electrode sheet.

[0038] In step S4), the punching unit may be spaced apart from the electrode sheet by a distance equal to or less than a distance at which at least a portion of the slotted positioning pin remains inserted into the recess of the electrode sheet.

[0039] Furthermore, the present invention provides an electrode formed using the electrode forming apparatus.

[0040] Beneficial Effects

[0041] As apparent from the above description, the electrode forming apparatus with slotted positioning pins and the electrode forming method using the same according to the present invention have the following effects compared with conventional electrode forming apparatuses: the problem of step formation at the electrode tab that may occur during slotting can be solved.

[0042] The effects of the present invention are that the zigzag defects that may occur in conventional electrode forming equipment can be eliminated, thereby 1) the upper and lower layers are precisely aligned with each other in the stacking process to manufacture the electrode assembly, thereby improving the efficiency of the battery, 2) there are no protruding portions of the electrode tabs, thereby preventing damage to the diaphragm and the occurrence of short circuits, and 3) when each electrode is rotated during the manufacture of the electrode assembly, the precise control of the position of the electrode and the criteria on which the electrode stacking is based become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a plan view showing a part of a conventional electrode manufacturing process.

[0044] Figure 2 is a schematic diagram showing a tortuosity defect of a groove in a conventional electrode manufacturing process.

[0045] Figure 3 is a perspective view of an electrode forming apparatus according to an embodiment of the present invention.

[0046] Figure 4are a perspective view and a cross-sectional view of a center punching unit according to an embodiment of the present invention.

[0047] Figure 5 Schematic diagram of the coupling relationship between the slotted positioning pin and the capturing recess according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] Now, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the preferred embodiments of the present invention. However, in describing the working principle of the preferred embodiments of the present invention in detail, when the detailed description of the known functions and structures incorporated herein may obscure the subject matter of the present invention, the detailed description will be omitted.

[0049] In addition, the same reference numerals will be used throughout the drawings to represent components that perform similar functions or operations. Where a component is referred to as being connected to another component throughout the application, the component may not only be directly connected to the other component, but the component may also be indirectly connected to the other component via another component. In addition, including a certain element does not mean excluding other elements, but means that other elements may be further included unless otherwise specified.

[0050] Furthermore, unless otherwise specifically limited, the description that specifies elements by limitation or addition is applicable to all inventions and does not limit the specific invention.

[0051] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0052] Figure 3 is a perspective view of an electrode forming apparatus according to an embodiment of the present invention, Figure 4 are perspective views and cross-sectional views of a center punch unit according to an embodiment of the present invention, Figure 5 Schematic diagram of the coupling relationship between the slotted positioning pin and the capturing recess according to an embodiment of the present invention.

[0053] Reference Figures 3 to 5 The electrode forming device according to the present invention includes: a sheet conveying unit (not shown) configured to move the electrode sheet 110 at a predetermined speed; a fixing unit 200 configured to fix the electrode sheet 110; and a punch unit, which is composed of a center punching unit 300 and a side punching unit (not shown) respectively configured to remove a central portion of the electrode sheet and a portion of the periphery of the electrode sheet by slotting, wherein the center punching unit 300 includes a hole punching member 310 and a slotting positioning pin 320.

[0054] The side punching unit is configured to perform slotting into special shapes, e.g. Figure 3 As shown, or the groove is performed into the shape of a common electrode tab, such as Figure 2 However, the present invention is not limited thereto.

[0055] The center punching unit 300 may include: a rectangular body 350 having a main axis along the moving direction A of the electrode sheet 110; a hole punching member 310 formed at the rear end of the rectangular body 350 along the moving direction A of the electrode sheet 110; and a slotted positioning pin 320 formed below the front end of the rectangular body 350 along the moving direction A of the electrode sheet 110.

[0056] The cuboid body 350 may be formed in a cuboid shape having a main axis along a moving direction A of the electrode sheet 110 , and may include a body punching surface 340 configured as a lower surface of the cuboid to punch the electrode sheet.

[0057] The hole punching member 310 may include: an expansion portion 312 extending from the rear end of the rectangular parallelepiped body 350 along the moving direction A of the electrode sheet 110, configured to increase the width of the main body punching surface of the punching electrode sheet at the expansion portion; a reduction portion 314 extending from the expansion portion 312, configured to reduce the width of the main body punching surface of the punching electrode sheet 110 at the reduction portion 314 along the main axis A; and a pin punching portion 316 extending from the reduction portion 314, the pin punching portion 316 being configured to punch a capture recess 116 for capturing the slotted positioning pin 320 in the electrode sheet 110. The capture recess 116 is formed in the electrode sheet 110, such as Figure 5 As shown by the dashed line, and formed in the electrode sheet 110, as shown in FIG. Figure 3 Shown in blue.

[0058] Although the slotted positioning pin is formed as Figures 3 to 5 , but the cross-section of the slotted positioning pin 320 may be any one of a circle, an arc, a wedge, a triangle, and a quadrilateral. Specifically, the wedge-shaped or triangular slotted positioning pin may be connected to the reduction portion 314 so as to align not only in the conveying direction A of the electrode sheet 110, but also in a direction perpendicular to the conveying direction A.

[0059] The fixing unit 200 may be provided with a middle groove 210 in the middle thereof, and the shape of the middle groove 210 corresponds to the center punching unit. The middle groove 210 may be formed to have a sufficient depth to allow the slotted positioning pin 320 to be inserted therein.

[0060] In addition, the present invention provides an electrode forming method using an electrode forming device, the electrode forming method comprising the following steps: S1) using a sheet conveying unit to convey an electrode sheet to a predetermined length; S2) conveying the electrode sheet or a stamping unit so that a slotted positioning pin is captured in a recess formed in the electrode sheet in a previous step of stamping; S3) pressing the electrode sheet using a stamping unit to press the electrode sheet; and S4) separating the stamping unit from the electrode sheet.

[0061] In step S4), the punching unit is spaced apart from the electrode sheet by a distance equal to or less than a distance by which at least a portion of the slotted positioning pin remains inserted into the recess of the electrode sheet.

[0062] As described above, the electrode forming apparatus having the slotted positioning pins and the electrode forming method using the same according to the present invention have the following effects compared with the conventional electrode forming apparatus: the problem of step formation at the electrode tab that may occur during slotting can be solved.

[0063] Those skilled in the art to which the present invention pertains will appreciate that various applications and modifications are possible within the scope of the present invention based on the above description.

[0064] (Explanation of reference numbers)

[0065] 110: Electrode sheet

[0066] 111: Periphery

[0067] 112: Longitudinal line

[0068] 113: Electrode contact

[0069] 114: First periphery

[0070] 115: Second outer week

[0071] 116: Capture recesses

[0072] 121: Uncoated part of electrode material

[0073] 120: Electrode material coating part

[0074] 130: Unit electrode sheet

[0075] 200: Fixed unit

[0076] 210: Middle groove

[0077] 300: Center punch unit

[0078] 310: Hole stamping components

[0079] 312: Expanded section

[0080] 314: Reduced part

[0081] 316: Pin stamping part

[0082] 320: Slotted locating pin

[0083] 340: Main stamping surface

[0084] 350: Cuboid body

[0085] A: Transmission direction

[0086] Industrial Applicability

[0087] The present invention relates to an electrode forming device and an electrode forming method using the same, wherein the electrode forming device has a slotted positioning pin configured to reduce a step that may occur during slotting of an electrode, and thus the present invention has industrial applicability.

Claims

1. An electrode forming device, comprising: a sheet conveying unit configured to move the electrode sheet at a predetermined speed; A fixing unit configured to fix the electrode sheet; and The punching unit is composed of a central punching unit and a side punching unit, wherein the central punching unit and the side punching unit are respectively configured to remove a central portion of the electrode sheet and a portion of an outer periphery of the electrode sheet by slotting, The central punching unit comprises a hole punching member and a slotted positioning pin, The central punching unit comprises: A rectangular parallelepiped body having a main axis along the moving direction of the electrode sheet; the hole punching member formed at a rear end of the rectangular parallelepiped body along a moving direction of the electrode sheet; and The slotted positioning pin is formed below the front end of the rectangular parallelepiped body along the moving direction of the electrode sheet.

2. The electrode forming device according to claim 1, wherein the rectangular body is formed into a rectangular shape, has a main axis along the moving direction of the electrode sheet, and the rectangular body includes a body stamping surface, and the body stamping surface is configured as the lower surface of the rectangular body to stamp the electrode sheet.

3. The electrode forming apparatus of claim 2, wherein the hole punching member comprises: an expansion portion extending from a rear end of the rectangular parallelepiped body along a moving direction of the electrode sheet, wherein a width of a punching surface of the body configured to punch the electrode sheet is increased at the expansion portion; a reduced portion extending from the expanded portion and configured such that a width of the main body punching surface for punching the electrode sheet is reduced at the reduced portion along the main axis; and A pin punching portion extends from the narrowed portion, and the pin punching portion is configured to punch a capture recess in the electrode sheet that captures the slotted positioning pin.

4. The electrode forming apparatus according to claim 1, wherein the cross-section of the slotted positioning pin is any one of a circle, an arc, a wedge, a triangle and a quadrilateral. 5 . The electrode forming apparatus according to claim 1 , wherein the fixing unit is provided with a middle groove in the middle of the fixing unit, and a shape of the middle groove corresponds to the center punching unit.

6. The electrode forming apparatus according to claim 5, wherein the intermediate groove is formed to have a sufficient depth to allow the slotted positioning pin to be inserted therein.

7. An electrode forming method using the electrode forming apparatus according to any one of claims 1 to 6, the electrode forming method comprising the following steps: S1) using the sheet conveying unit to convey the electrode sheet to a predetermined length; S2) conveying the electrode sheet or the punching unit so that the slotted positioning pins are captured in recesses formed in the electrode sheet in a previous step of punching; S3) using the punching unit to press the electrode sheet to punch the electrode sheet; and S4) separating the punching unit from the electrode sheet.

8. The electrode forming method according to claim 7, wherein: In step S4), the punching unit is spaced apart from the electrode sheet by a distance equal to or less than a distance at which at least a portion of the slotted positioning pin remains inserted into the recess of the electrode sheet.

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