Electrode manufacturing method including folding and electrode sheet including folding

Abstract

The present invention relates to an electrode manufacturing method of manufacturing a foldable battery cell, the method including: a coating step of forming an electrode mixture coating portion on an electrode sheet so as to include an uncoated portion not having the electrode mixture formed thereon by coating; a step of cutting the electrode sheet into a plurality of unit electrode sheets; and a step of making a cut in the cut electrode sheet, wherein the uncoated portion includes: a first uncoated portion formed parallel to a direction in which the electrode sheet is taken out; and a second uncoated portion formed perpendicular to the direction in which the electrode sheet is taken out.

Description

TECHNICAL FIELD

[0001] This application claims priority to Korean Patent Application No. 2020-0069118, filed on June 8, 2020, the disclosure of which is incorporated herein in its entirety by reference.

[0002] The present application relates to an electrode manufacturing method including a folding portion and an electrode sheet including the folding portion, and more particularly, to an electrode manufacturing method including a folding portion that can be used to manufacture a foldable battery cell and an electrode sheet including the folding portion. BACKGROUND

[0003] Lithium secondary batteries capable of charging and discharging have been widely used as energy sources for wireless mobile devices or wearable devices, and have also been used as energy sources for electric vehicles and hybrid electric vehicles that have emerged as alternatives to existing gasoline and diesel vehicles that cause air pollution.

[0004] In addition, as the number of small multifunctional product types and the trend of design in electronic devices have increased, the number of products based on new shapes, such as shapes including curved surfaces or geometric shapes, rather than conventional simple structures, such as planar structures and prismatic structures, has increased.

[0005] In order to apply lithium secondary batteries to products having various shapes, lithium secondary batteries having various shapes, such as trapezoidal and polygonal shapes, rather than rectangular shapes, have been developed.

[0006] For example, for smartphones, the sides are curved to improve the grip feeling, and flexible display products capable of being curved or folded have emerged.

[0007] In the case of using a rectangular battery cell in a bendable or foldable device, there is a problem of a large amount of dead space being formed. Therefore, even if the battery cell is installed in a device having an atypical shape, a battery cell capable of reducing the dead space while securing the capacity must be developed.

[0008] In relation to this, Patent Document 1 discloses a secondary battery configured such that a positive active material layer and a negative active material layer are formed by coating such that they are spaced apart from each other by a predetermined distance, and the positive active material layer and the negative active material layer include a curved region configured to be curved at an uncoated portion in which the positive active material layer and the negative active material layer are not coated.

[0009] However, the secondary battery disclosed in Patent Document 1 is suitable for application to a long device, but there is a problem that a plurality of curved regions are formed, so that the uncoated portion is widened, and thus the energy density is reduced.

[0010] Patent Document 2 relates to a battery cell including: a current collector having at least one uncoated portion that separates an electrode mixture, wherein a portion of the battery case in which the uncoated portion is located is bent, whereby the shape of the battery cell is changed.

[0011] In Patent Document 2, the electrode assembly is separated from the battery case, whereby there is a problem that the bent portion of the battery case and the bent portion of the electrode assembly can be misaligned with each other when the battery cell is bent.

[0012] Patent Document 3 discloses an electrode configured to have a structure in which an electrode active material is printed on a belt-type current collector so as to have a pattern that is repeated at a certain interval.

[0013] However, the invention disclosed in Patent Document 3 relates to an electrode that is cut to have a predetermined length and width, in which the electrode is accommodated in a sheathing member in a bent state.

[0014] As can be seen from the above description, each of the above-described patent documents only discloses an electrode including an uncoated portion of an uncoated electrode mixture. Therefore, there is a need for a method of manufacturing an electrode having the above-described structure or a study on the shape of an electrode sheet.

[0015] (Prior Art Documents)

[0016] (Patent Document 1) Korean Patent Application Publication No. 2012-0022385 (2012.03.12)

[0017] (Patent Document 2) Korean Patent Application Publication No. 2017-0033513 (2017.03.27)

[0018] (Patent Document 3) Japanese Patent Application Publication No. 1995-153438 (1995.06.16) SUMMARY

[0019] TECHNICAL PROBLEM

[0020] The present invention has been completed in view of the above-described problems, and one object of the present invention is to provide an electrode manufacturing method and an electrode sheet including a folded portion, the electrode including a folded portion constituted by an uncoated portion that does not have an electrode mixture formed thereon by coating, in order to manufacture an electrode for a foldable battery cell.

[0021] TECHNICAL SOLUTION

[0022] To achieve the above object, an electrode manufacturing method according to the present application includes: a coating step of forming an electrode mixture coating portion on an electrode sheet so as to include an uncoated portion which does not have the electrode mixture formed thereon by coating; a slitting step of slitting the electrode sheet into a plurality of unit electrode sheets; and a notch step of making a notch in the slit electrode sheet, wherein the uncoated portion includes: a first uncoated portion formed in parallel with a direction in which the electrode sheet is taken out; and a second uncoated portion formed in perpendicular to the direction in which the electrode sheet is taken out.

[0023] In the electrode manufacturing method according to the present application, the slitting step can be a step of slitting the coating portion between the first uncoated portion and another first uncoated portion adjacent to the first uncoated portion.

[0024] In the electrode manufacturing method according to the present application, the second uncoated portion can be a folding portion, and the notch step can be a step of slitting the coating portion between the second uncoated portion and another second uncoated portion adjacent to the second uncoated portion to manufacture a unit electrode.

[0025] In the electrode manufacturing method according to the present application, the second uncoated portion can include a notch portion and a folding portion, the notch portion and the folding portion can be alternately arranged, and a unit electrode can be manufactured by making a notch in the notch portion.

[0026] Further, the electrode manufacturing method can include a step of forming the uncoated portion so that a width of the notch portion and a width of the folding portion are different from each other.

[0027] In the electrode manufacturing method according to the present application, the notch step can include: a notch process for forming an electrode tab on the first uncoated portion; and a coating portion notch process for manufacturing a unit electrode.

[0028] Further, the notch process for forming an electrode tab and the coating portion notch process can be simultaneously performed.

[0029] In the electrode manufacturing method according to the present application, the notch step can include: a notch process for forming an electrode tab on the first uncoated portion; and a coating portion notch process for manufacturing a unit electrode.

[0030] In the electrode manufacturing method according to the present application, the notch process for forming an electrode tab and the coating portion notch process can be simultaneously performed.

[0031] An electrode tab according to the present application includes a coated portion having an electrode mixture formed thereon by coating, and an uncoated portion having no electrode mixture formed thereon by coating, wherein the uncoated portion includes a first uncoated portion formed in parallel with a direction in which the electrode tab is taken out, and a second uncoated portion formed in perpendicular to the direction in which the electrode tab is taken out, the first uncoated portion is an electrode tab formation portion, and the second uncoated portion includes a cutout portion and a folded portion.

[0032] In the electrode tab according to the present application, the cutout portion and the folded portion can be alternately arranged.

[0033] An electrode tab formation portion can be formed at a boundary between any one of a first coated portion and a second coated portion formed on opposite sides of the folded portion and a portion in which an electrode tab is to be formed.

[0034] In the electrode tab according to the present application, the first coated portion and the second coated portion are formed to have the same size.

[0035] In the electrode tab according to the present application, a width of the folded portion can be formed to be greater than a width of the cutout portion.

[0036] In the electrode tab according to the present application, a width of the folded portion can be greater than a thickness of the coated portion x π.

[0037] Advantageous Effects

[0038] As is apparent from the foregoing description, in the electrode manufacturing method according to the present application, in order to form not only an uncoated portion that is an electrode tab formation portion but also an uncoated portion configured to manufacture a folded electrode on an electrode tab, a method of coating a portion of the electrode tab with an electrode mixture is used, whereby as compared to a method of coating an entire electrode tab with an electrode mixture and then removing the coating, the number of manufacturing steps can be reduced, and defects that can occur in the coating removal process can be reduced.

[0039] Further, in the cutting process for manufacturing a unit electrode, the cutting is performed so that the unit electrode includes a folded portion, whereby a unit electrode having a coated portion and an uncoated portion formed to have a regular region can be obtained.

[0040] Further, when the cutting is performed so that the unit electrode includes a folded portion, an electrode tab is formed at every other coated portion of the coated portions formed on opposite sides of a portion in which an electrode tab is formed in a direction in which the electrode tab is taken out. Thus, when the unit electrodes are stacked, the electrode tabs can overlap in a direction in which the unit electrodes are stacked. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a plan view of an electrode sheet according to one embodiment;

[0042] Figure 2 is a plan view of an electrode sheet according to one embodiment; Figure 1 is a plan view of a cutout portion formed in the electrode sheet of

[0043] Figure 3 is a plan view of an electrode sheet according to another embodiment;

[0044] Figure 4 is a plan view of an electrode sheet according to another embodiment; Figure 3 is a vertical sectional view of the electrode sheet of DETAILED DESCRIPTION

[0045] Now, preferred embodiments of the present application will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present application pertains can easily practice the preferred embodiments of the present application. However, when it is possible to obscure the subject matter of the present application, detailed descriptions of known functions and configurations included herein will be omitted.

[0046] Further, the same reference numerals will be used to designate the same components throughout the drawings. In the case where one part is described as being connected to another part in the specification, the one part can be directly connected to the other part, or the one part can be indirectly connected to the other part via yet another part. Further, the inclusion of certain elements does not mean the exclusion of other elements, but means the further inclusion of the elements unless otherwise specified.

[0047] Embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0048] Figure 1 is a plan view of an electrode sheet according to one embodiment.

[0049] The electrode manufacturing method according to the present application includes a coating step of forming an electrode mixture coating portion on an electrode sheet, thereby including an uncoated portion having no electrode mixture formed thereon by coating, a step of cutting the electrode sheet into a plurality of unit electrode sheets, and a step of making a cut in the cut electrode sheet.

[0050] Referring to Figure 1 , an electrode mixture coating portion 110 is formed on the electrode sheet while the electrode sheet is taken out in the arrow direction. At this time, the coating portion 110 is formed such that an uncoated portion having no electrode mixture formed thereon by coating is formed, in which a first uncoated portion 120 is formed in parallel with the direction in which the electrode sheet is taken out, and a second uncoated portion 130 is formed in perpendicular to the direction in which the electrode sheet is taken out.

[0051] The coating portion can be formed on any one of the upper surface and the lower surface of the electrode tab, or can be formed on both opposite surfaces of the electrode tab.

[0052] The first uncoated portion 120 is an electrode tab forming portion, and the electrode tab 102 of the unit electrode 101 is formed at the first uncoated portion 120.

[0053] The second uncoated portion 130 is a folding portion, which is a portion where the electrode is folded, and the unit electrode 101 is cut to include the second uncoated portion 130.

[0054] That is, the first coating portion 110a and the second coating portion 110b are formed on opposite sides of the second uncoated portion 130, the electrode tab is formed at any one of the first coating portion 110a and the second coating portion 110b, and the first coating portion 110a and the second coating portion 110b have the same size.

[0055] The electrode tab is cut into a plurality of unit electrode tabs 150, and a cutting line 140 is formed on the coating layer. Thus, two unit electrode tabs 150 are formed from the electrode tab of Figure 1

[0056] However, the coating portion and the uncoated portion can be formed so that two or more cutting lines are formed according to the width of the electrode tab and the size of the unit electrode, and the cutting line can be formed to divide the coating portion into two equal parts.

[0057] That is, the cutting step can be performed using a method of cutting the coating portion 110 located between the first uncoated portion 120 and another first uncoated portion 120 adjacent to the first uncoated portion 120.

[0058] Figure 2 is a plan view showing a cut portion formed in the electrode tab of Figure 1

[0059] Referring to Figure 2 , the cutting step is a process of punching the electrode tab along the outer periphery of the electrode tab and the unit electrode, in which, in order to form the unit electrode 101 indicated by a thick dotted line, the electrode tab 102 and the coating portion 110 located between the second uncoated portion 130 and another second uncoated portion 130 adjacent to the second uncoated portion 130 are cut to manufacture the unit electrode.

[0060] The cutting step includes a cut step for forming the electrode tab 102 on the first uncoated portion 120 and a coating portion cut step for manufacturing the unit electrode, and the cut step for forming the electrode tab and the coating portion cut step can be sequentially performed.

[0061] ​​Alternatively, the cut process for forming the electrode tab and the coating portion cut process can be simultaneously performed. In the case where the cut process for forming the electrode tab and the coating portion cut process are simultaneously performed, the electrode manufacturing time can be reduced.

[0062] Figure 3 is a plan view of an electrode sheet according to another embodiment.

[0063] Referring to Figure 3 The coating portion 210 is formed at the electrode sheet while the electrode sheet is taken out in the arrow direction. At this time, the coating portion 210 is formed such that an uncoated portion not having an electrode mixture formed thereon by coating is formed, in which a first uncoated portion 220 is formed in parallel with the direction in which the electrode sheet is taken out, and a second uncoated portion 230 is formed in perpendicular to the direction in which the electrode sheet is taken out.

[0064] The first uncoated portion 220 is an electrode tab forming portion, and the electrode tab 202 of the unit electrode 201 represented by a thick solid line is formed at the first uncoated portion 220.

[0065] The second uncoated portion 230 includes a folding portion 231, which is a portion where the electrode is folded, and a cut portion 232.

[0066] In the present application, the unit electrode is formed to include the folding portion 231. The folding portion 231 and the cut portion 232 are alternately arranged in the direction in which the electrode sheet is taken out, in addition to the coating portion.

[0067] The first coating portion 210a and the second coating portion 210b are formed on opposite sides of the folding portion 231 of the second uncoated portion 230, the electrode tab is formed at any one of the first coating portion 210a and the second coating portion 210b, and the first coating portion 210a and the second coating portion 210b have the same size.

[0068] In Figure 3 In the electrode sheet of Figure 1 and Figure 2 Unlike the electrode sheet of In the case where the cut portion 232 is widened, the coating portion is narrowed, and thus the capacity of the battery cell can be reduced. However, in the case where the cut portion 232 is punched to manufacture the unit electrode, it is possible to prevent the occurrence of a problem in which the electrode mixture layer is separated from the coating portion in the case where the coating portion is punched or the coating portion is contaminated due to powder generated from the electrode mixture layer.

[0069] In Figure 3The step of cutting the electrode tab includes a cut-out process of forming the electrode tab 202 on the first uncoated portion 220 and a cut-out process of the cut-out portion 232 for manufacturing the unit electrode 201. The cut-out process for forming the electrode tab and the cut-out portion cut-out process can be sequentially performed.

[0070] Alternatively, the cut-out process for forming the electrode tab and the cut-out portion cut-out process can be simultaneously performed. In the case of simultaneously performing the cut-out process for forming the electrode tab and the cut-out portion cut-out process, the electrode manufacturing time can be reduced.

[0071] Figure 4 is Figure 3 a vertical sectional view of the electrode tab.

[0072] Referring to Figure 4 , assuming that the direction in which the electrode tab is taken out is the width W2 direction of the cut-out portion 232 and the width W1 direction of the folding portion 231, the width W2 of the cut-out portion 232 and the width W1 of the folding portion 231 can be formed to be different from each other. For example, the width W2 of the cut-out portion 232 can be formed to be smaller than the width W1 of the folding portion 231.

[0073] The folding portion 231 is disposed to face each other in a state in which the electrode is folded. Preferably, the width W1 of the folding portion 231 is at least 1 / 2 of the circumference of a circle having the thickness H of the coated portion as a radius. Accordingly, the width W1 of the folding portion 231 can be formed to be greater than the thickness H x π of the coated portion.

[0074] It will be understood by those skilled in the art, based on the foregoing description, that various applications and modifications can be made within the scope of the present application.

[0075] (Explanation of reference numerals)

[0076] 101, 201: unit electrode

[0077] 102, 202: electrode tab

[0078] 110, 210: coated portion

[0079] 110a, 210a: first coated portion

[0080] 110b, 210b: second coated portion

[0081] 120, 220: first uncoated portion

[0082] 130, 230: second uncoated portion

[0083] 140, 240: cutting line

[0084] 150: unit electrode tab

[0085] 231: fold portion

[0086] 232: cut portion

[0087] H: thickness of coating portion

[0088] W1: width of fold portion

[0089] W2: width of cut portion

[0090] [Industrial applicability]

[0091] As is apparent from the foregoing description, according to the electrode manufacturing method of the present application, in order to form not only the uncoated portion as the electrode tab forming portion on the electrode sheet but also the uncoated portion configured to manufacture a folded electrode on the electrode sheet, a method of coating a portion of the electrode sheet with an electrode mixture is used, so that the number of manufacturing steps can be reduced and defects that can occur in the coating removal process can be reduced, as compared with a method of coating the entire electrode sheet with an electrode mixture and then removing the coating.

[0092] Further, in the cutting process for manufacturing the unit electrode, the cutting is performed so that the fold portion is included in the unit electrode, so that a unit electrode having a coating portion and an uncoated portion formed to have a regular area can be obtained.

[0093] Further, when the cutting is performed so that the fold portion is included in the unit electrode, the electrode tab is formed at every other one of the coating portions formed on opposite sides of the portion where the electrode tab is to be formed in the direction in which the electrode sheet is taken out. Therefore, when the unit electrodes are stacked, the electrode tabs can overlap in the direction in which the unit electrodes are stacked.

Claims

1. A method for manufacturing an electrode, comprising: The coating step involves forming an electrode mixture coated portion on an electrode sheet such that the electrode sheet includes an uncoated portion, the uncoated portion of which does not have the electrode mixture formed by the coating. The cutting step of cutting the electrode sheet into multiple unit electrode sheets; as well as The cutting step of making a cut on the electrode sheet being cut. The uncoated portion includes: A first uncoated portion, the first uncoated portion being formed parallel to the direction in which the electrode sheet is removed; and The second uncoated portion is formed perpendicular to the direction in which the electrode sheet is removed. in, The second uncoated portion includes a cut-out portion and a folded portion. The cut-out portion and the folded portion are alternately arranged, and The unit electrode is manufactured by making cuts in the cut portion.

2. The electrode manufacturing method according to claim 1, wherein, The cutting step is the step of cutting the coated portion located between the first uncoated portion and another first uncoated portion adjacent to the first uncoated portion.

3. The electrode manufacturing method according to claim 1, wherein, The second uncoated portion is a folded portion, and In the cutting step, a coated portion located between the second uncoated portion and another second uncoated portion adjacent to the second uncoated portion is cut to manufacture a unit electrode.

4. The electrode manufacturing method according to claim 1, comprising the following steps: The uncoated portion is formed such that the width of the cut portion is different from the width of the folded portion.

5. The electrode manufacturing method according to claim 3, wherein, The incision step includes: A cutting process for forming electrode terminals on the first uncoated portion; and Cutting process for coating section used in manufacturing unit electrodes.

6. The electrode manufacturing method according to claim 5, wherein, Simultaneously, the cutting process for forming the electrode terminal piece and the coating section cutting process are performed.

7. The electrode manufacturing method according to claim 1, wherein, The incision step includes: A cutting process for forming electrode terminals on the first uncoated portion; and Cutting process for coating section used in manufacturing unit electrodes.

8. The electrode manufacturing method according to claim 7, wherein, Simultaneously, the cutting process for forming the electrode terminal piece and the coating section cutting process are performed.

9. An electrode sheet, comprising: A coating section having an electrode mixture formed by coating; as well as Uncoated portions, wherein the uncoated portions do not have the electrode mixture formed by coating, The uncoated portion includes: A first uncoated portion, the first uncoated portion being formed parallel to the direction in which the electrode sheet is removed; and The second uncoated portion is formed perpendicular to the direction in which the electrode sheet is removed. The first uncoated portion is an electrode terminal forming portion, and The second uncoated portion includes a cut-out portion and a folded portion. in, The cut-out portion and the folded portion are alternately arranged. The unit electrode is manufactured by making cuts in the cut portion.

10. The electrode sheet according to claim 9, wherein, An electrode connector is formed at the boundary between either the first coating portion or the second coating portion formed on opposite sides of the folded portion and the portion where the electrode connector will be formed.

11. The electrode sheet according to claim 10, wherein, The first coating portion and the second coating portion are formed to have the same size.

12. The electrode sheet according to claim 9, wherein, The width of the folded portion is greater than the width of the cut portion.

13. The electrode sheet according to claim 9, wherein, The width of the folded portion is greater than the thickness of the coated portion by π.

Images