A method for manufacturing electrodes including folded portions and an electrode sheet including folded portions.

Abstract

The present invention relates to a manufacturing method for manufacturing an electrode of a foldable battery cell, the method including: a coating step of forming an electrode mixture coating portion on an electrode sheet to include an uncoated portion uncoated with an electrode mixture; 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 an electrode tab forming portion formed parallel to a withdrawal direction of the electrode sheet and a folding portion.

Description

Technical Field

[0001] This application claims the benefit of priority to Korean Patent Application No. 2020-0070046, filed on June 10, 2020, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to a method for manufacturing an electrode including a folded portion and an electrode sheet including the folded portion, and more specifically, the present invention relates to a method for manufacturing an electrode including a folded portion and an electrode sheet including the folded portion that can be used to manufacture a foldable battery cell. Background Technology

[0003] Rechargeable and dischargeable lithium-ion batteries have been widely used as an energy source for wireless mobile devices or wearable devices, and have also been proposed as an energy source for electric and hybrid vehicles as alternatives to existing gasoline and diesel vehicles that cause air pollution.

[0004] Furthermore, with the increase in miniaturized and multifunctional products and the trend of emphasizing the design of electronic devices, the number of products based on new shapes, such as those including curves or geometric shapes, rather than traditional simple structures such as planar and prismatic structures, has increased.

[0005] In order to apply lithium secondary batteries to products with various shapes, lithium secondary batteries with various shapes other than rectangles (e.g., stepped and polygonal) have been developed.

[0006] For example, smartphones have curved sides to improve grip, and flexible display products that can be bent or folded have emerged.

[0007] When using rectangular battery cells in flexible or foldable devices, there is a significant problem of dead zones. Therefore, it is necessary to develop battery cells that can reduce dead zones while ensuring capacity, even when installed in devices with atypical shapes.

[0008] In this regard, Patent Document 1 discloses a secondary battery configured such that a positive electrode active material layer and a negative electrode active material layer are formed by coating to be spaced apart from each other by a predetermined distance and include a curved region configured to be curved at the uncoated portion where neither the positive electrode active material layer nor the negative electrode active material layer is coated.

[0009] The secondary battery disclosed in Patent Document 1 is suitable for elongated devices, but it has the problem of forming multiple curved regions, which widens the uncoated portion and thus reduces the energy density.

[0010] Patent document 2 relates to a battery cell including a current collector having at least one uncoated portion separating an electrode mixture, wherein a portion of the battery casing containing the uncoated portion is bent, thereby changing the shape of the battery cell.

[0011] In Patent Document 2, the electrode assembly is separated from the battery casing, which raises the problem that the bent portion of the battery casing and the bent portion of the electrode assembly may misalign when the battery cell is bent.

[0012] Patent document 3 discloses an electrode configured to have a structure in which electrode active material is printed on a strip-shaped electrode current collector to have a pattern that repeats at regular intervals.

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

[0014] As can be seen from the above description, each of the aforementioned patent documents only discloses an electrode including an uncoated portion that is not coated with the electrode mixture. Therefore, there is a need for a method for manufacturing an electrode with the above structure or for research on the shape of the electrode sheet.

[0015] (Existing technical literature)

[0016] (Patent Document 1) Korean Patent Application Publication No. 2012-0022385 (March 12, 2012)

[0017] (Patent Document 2) Korean Patent Application Publication No. 2017-0033513 (March 27, 2017)

[0018] (Patent Document 3) Japanese Patent Application Publication No. 1995-153438 (June 16, 1995) Summary of the Invention

[0019] Technical issues

[0020] The present invention was made in view of the above-mentioned problems, and the object of the present invention is to provide a method for manufacturing an electrode including a folded portion (consisting of an uncoated portion on which an electrode mixture is formed without coating) for manufacturing an electrode for a foldable battery cell, and also to provide an electrode sheet including a folded portion.

[0021] Technical solution

[0022] To achieve the above objectives, the electrode manufacturing method according to the present invention includes: a coating step of forming an electrode mixture coating portion and an uncoated portion of the electrode sheet on which the electrode mixture is formed; a cutting step of cutting the electrode sheet into a plurality of unit electrode sheets; and a cutting step of making cuts on the cut electrode sheets, wherein the uncoated portion includes an electrode terminal forming portion and a folded portion formed parallel to the direction in which the electrode sheet is removed.

[0023] In the electrode manufacturing method according to the present invention, the coating portion can be continuously shaped to be parallel to the direction in which the electrode sheet is removed.

[0024] In the electrode manufacturing method according to the present invention, the cutting step may be the step of cutting the coating portion located between the folded portion and another folded portion adjacent to the folded portion.

[0025] The electrode manufacturing method according to the present invention may include the step of forming an uncoated portion such that the width of the electrode terminal forming portion and the width of the folded portion are different from each other.

[0026] In the electrode manufacturing method according to the present invention, the cutting step may include a cutting process for forming an electrode terminal at the electrode terminal forming portion and a process for cutting the unit electrode sheet along the cutting line to divide the unit electrode sheet.

[0027] In addition, the cutting process for forming electrode terminals and the process of cutting unit electrode plates along the cutting line can be performed simultaneously.

[0028] In the electrode manufacturing method according to the present invention, electrode terminal forming portions may be formed on opposite side ends and the central portion of the removed electrode terminal.

[0029] The electrode sheet can be cut into unit electrode sheets with two widths.

[0030] The electrode sheet according to the invention includes a coated portion on which an electrode mixture is formed and an uncoated portion on which the electrode mixture is not formed, wherein the uncoated portion includes an electrode terminal forming portion and a folded portion formed parallel to the direction in which the electrode sheet is removed.

[0031] In the electrode sheet according to the present invention, the coating portion, the electrode terminal forming portion, and the folding portion can be formed symmetrically about the cutting line.

[0032] In the electrode sheet according to the present invention, the folded portion may be an uncoated portion formed between the cutting line and the electrode terminal forming portion.

[0033] In the electrode sheet according to the invention, the first coating portion and the second coating portion may be formed on opposite sides of the folded portion, and the first coating portion and the second coating portion may be formed to have the same size.

[0034] In the electrode sheet according to the present invention, the width of the folded portion can be greater than the thickness of the coated portion × π.

[0035] Furthermore, the present invention provides a battery cell including electrodes manufactured using an electrode manufacturing method, wherein the battery cell is configured to be flexible at the folds of the electrodes.

[0036] Beneficial effects

[0037] As can be clearly seen from the above description, in the electrode manufacturing method according to the present invention, in order to form not only an uncoated portion as an electrode terminal forming portion on the electrode sheet, but also an uncoated portion configured to manufacture a folded electrode, a method of coating a portion of the electrode sheet with an electrode mixture is used. Thus, compared with the method of coating the entire electrode sheet with an electrode mixture and then removing the coating, the number of manufacturing steps can be reduced, and defects that may occur during the coating removal process can be reduced.

[0038] Furthermore, in the slitting process used to manufacture the unit electrode, the slitting is performed such that the folded portion is included in the unit electrode, thereby obtaining a unit electrode having a coated portion and an uncoated portion formed with regular areas.

[0039] Furthermore, foldable battery cells can be manufactured using electrode assemblies including electrodes according to the invention, thus providing battery cells that can be used in devices having bent or folded shapes. Attached Figure Description

[0040] Figure 1 This is a plan view of the electrode sheet according to an embodiment.

[0041] Figure 2 This is a plan view of the electrode sheet according to another embodiment.

[0042] Figure 3 It shows that it was formed in Figure 1 A plan view of the cut portion in the electrode sheet.

[0043] Figure 4 yes Figure 3 A vertical cross-sectional view of the electrode sheet. Detailed Implementation

[0044] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, enabling those skilled in the art to readily implement these preferred embodiments. However, in describing the working principle of the preferred embodiments of the invention in detail, detailed descriptions of known functions and configurations included herein will be omitted where such descriptions might obscure the subject matter of the invention.

[0045] Furthermore, the same reference numerals will be used in all the accompanying drawings to refer to parts that perform similar functions or operations. Where one part is described throughout the specification as connected to another part, this can mean not only that one part is directly connected to the other, but also that one part can be indirectly connected to another part through yet another part. Moreover, including an element does not imply the exclusion of other elements, but rather means that, unless otherwise specified, these elements may be further included.

[0046] Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0047] Figure 1 This is a plan view of the electrode sheet according to an embodiment.

[0048] Reference Figure 1 Remove electrode 100 in the direction of the arrow. Figure 1 The beginning portion of the removed electrode sheet is shown.

[0049] The electrode manufacturing method according to the present invention includes: a coating step of forming an electrode mixture coating portion and an uncoated portion thereon without coating the electrode mixture coating portion; a cutting step of cutting the electrode sheet into a plurality of unit electrode sheets; and a cutting step of making cuts on the cut electrode sheets.

[0050] Reference Figure 1 While removing the electrode sheet in the direction of the arrow, an electrode mixture coating portion 110 is formed on the electrode sheet 100. At this time, the coating portion 110 is formed, thereby forming an uncoated portion where the electrode mixture is formed.

[0051] The coating portion 110 can be formed on either the upper or lower surface of the electrode sheet, or on the opposite surface of the electrode sheet.

[0052] The uncoated portion includes an electrode tab forming portion 120 and a folded portion 130, the folded portion 130 being formed to extend in a direction parallel to the direction in which the electrode tab is removed.

[0053] In the electrode sheet according to the present invention, the uncoated portion and the coated portion are continuously formed in a direction parallel to the direction in which the electrode sheet is removed.

[0054] A cutting line 140 is formed in the center of the electrode sheet 100 along the direction in which the electrode sheet is removed, and the coating portion 110, the electrode terminal forming portion 120 and the folding portion 130 are formed symmetrically with respect to the cutting line 140.

[0055] The cutting line refers to the initial cutting line along which the cutter moves during the cutting process to divide the coated area.

[0056] The cutting step is performed by cutting the coating portion 110 located between the folded portion 130 and another folded portion 130 adjacent to the folded portion. At this time, in order to manufacture electrodes with uniform dimensions, the cutting line 140 is set at the position where the coating portion 110 is divided into two equal parts.

[0057] The folded portion 130 is an uncoated portion formed between the cutting line 140 and the electrode terminal forming portion 120. When manufacturing a battery cell that includes an electrode assembly made using unit electrodes formed through a cutting and slit process and then folding it, the folded portion is set to be an uncoated portion with an electrode mixture formed thereon to prevent the electrode mixture from separating from the electrode current collector.

[0058] Simultaneously, when the positive and negative electrodes, formed by cutting and slits, are stacked with partitions inserted between them, to prevent the positive and negative electrode terminals from contacting each other in the stacking direction, the electrode terminals can be formed such that the outer periphery of the electrode protruding from the electrode terminal is offset to one side. Therefore, as... Figure 1 As shown, the electrode terminals formed on opposite sides of the electrode terminal forming section 120 in the direction in which the electrode terminal is taken out are formed to not overlap.

[0059] The present invention relates to an electrode manufacturing method and electrode sheet for manufacturing an electrode based on x-axis folding, wherein a first coating portion 110a and a second coating portion 110b are formed on opposite sides of a unit electrode 101 formed by cutting and slits, based on a folded portion 130.

[0060] When the electrode is folded, the first coating portion 110a and the second coating portion 110b face each other, so the first coating portion and the second coating portion can be formed to have the same size.

[0061] Figure 2 This is a plan view of the electrode sheet according to another embodiment.

[0062] Reference Figure 2 Remove electrode 200 in the direction of the arrow. Figure 2 The beginning portion of the removed electrode sheet is shown.

[0063] and Figure 1 The electrode plates are different. Figure 2 The electrode sheet 200 is configured to have a structure in which electrode terminal forming portion 220a is formed at each of the opposite two ends of the removed electrode sheet 200, and electrode terminal forming portion 220b is formed at the central portion of the electrode sheet 200.

[0064] Furthermore, the coating portion 210, the folding portion 230, and the coating portion 210 are formed sequentially from the electrode terminal forming portion 220a along the inward direction of the electrode sheet 200.

[0065] In other words, the coating portion 210 is formed on opposite sides of the folded portion 230, and this form can be described as the coating portion 210 having the folded portion 230 formed in the middle.

[0066] Furthermore, based on the electrode terminal forming portion 220b at the central portion of the electrode sheet 200 in the direction in which the electrode sheet 200 is taken out, a coating portion 210 including a folded portion 230 is formed on the upper and lower portions of the electrode sheet 200, respectively.

[0067] Electrode sheet 200 has a structure in which the electrode sheet is cut along two cutting lines 240 to form three unit electrode sheets 251, 252, and 253. Unit electrode sheets 251 and 253 have the same width, and the width of unit electrode sheet 252 is formed to be greater than the width of each of unit electrode sheets 251 and 253. Therefore, in electrode sheet 200, in a structure where electrode terminal forming portions are formed at opposite side ends and the central portion of the electrode sheet, unit electrode sheets with two different widths are formed.

[0068] The cutting step is performed by forming a cutting line 240 at the coating portion 210 located between the folds 230 and cutting the coating portion along the cutting line 240.

[0069] Figure 3 It is shown in Figure 1 A plan view of the cut portion formed in the electrode sheet.

[0070] refer to Figure 3 The cutting step includes a cutting process for forming an electrode terminal 102 at the electrode terminal forming portion 120 and a process for cutting the electrode sheet along the cutting line 122 to divide the electrode sheet into unit electrode sheets 150.

[0071] Cutting lines 140 that divide the electrode sheet 100 into multiple unit electrode sheets 150 are formed on the coating portion 110, and the cut lines 122 are formed perpendicular to the cutting lines 140 and are formed in a straight line shape that passes through the coating portion 110 and the folded portion 130.

[0072] The cutting process for forming the electrode contacts and the cutting process for cutting the electrode contacts along the cut line can be performed sequentially. Alternatively, the cutting process for forming the electrode contacts and the cutting process for cutting the electrode contacts along the cut line can be performed simultaneously.

[0073] By simultaneously performing the cutting process for forming electrode terminals and the cutting process for the electrode terminals along the cutting line, electrode manufacturing time can be reduced.

[0074] Figure 4 yes Figure 3A vertical cross-sectional view of the electrode sheet.

[0075] Reference Figure 4 , Figure 4 It is along Figure 3 A vertical cross-sectional view of the electrode sheet taken along the x-axis.

[0076] The uncoated portion can be formed such that the width W1 of the electrode tab forming portion 120 and the width W2 of the folded portion 130 are different from each other. For example, when considering that the electrode tabs are not formed in an overlapping structure, the width W1 of the electrode tab forming portion 120 can be formed to be smaller than the width W2 of the folded portion 130. Alternatively, depending on the size of the electrode tabs, the width W1 of the electrode tab forming portion 120 can be formed to be larger than the width W2 of the folded portion 130.

[0077] The folded portions 130 are configured to face each other when the electrodes are folded. Preferably, the width W2 of the folded portion 130 is at least half the circumference of a circle with a radius H equal to the thickness H of the coating portion. Therefore, the width W2 of the folded portion 130 can be formed to be greater than the thickness H × π of the coating portion.

[0078] Those skilled in the art will understand that, based on the above description, various applications and modifications can be made within the scope of this invention.

[0079] (Explanation of reference numerals in the attached diagram)

[0080] 100, 200: Electrode plates

[0081] 101: Unit Electrode

[0082] 102: Electrode connector

[0083] 110, 210: Coating section

[0084] 110a: First coating section

[0085] 110b: Second coating section

[0086] 120, 220a, 220b: Electrode terminal forming section

[0087] 122: Incision line

[0088] 130, 230: Folding section

[0089] 140, 240: Cut-off lines

[0090] 150, 251, 252, 253: Unit electrode plates

[0091] H: Thickness of the coated area

[0092] W1: Width of the electrode terminal block forming portion

[0093] W2: Width of the folded section

[0094] Industrial application

[0095] As can be clearly seen from the above description, in the electrode manufacturing method according to the present invention, in order to form not only an uncoated portion as an electrode terminal forming portion on the electrode sheet, but also an uncoated portion configured to manufacture a folded electrode, a method of coating a portion of the electrode sheet with an electrode mixture is used. Thus, compared with the method of coating the entire electrode sheet with an electrode mixture and then removing the coating, the number of manufacturing steps can be reduced, and defects that may occur in the coating removal process can be reduced.

[0096] Furthermore, in the slitting process used to manufacture the unit electrode, the slitting is performed so that the folded portion is included in the unit electrode, thereby obtaining a unit electrode having a coated portion and an uncoated portion formed as a regular area.

[0097] Furthermore, foldable battery cells can be manufactured using electrode assemblies including electrodes according to the invention, thus providing battery cells that can be used in devices having bent or folded shapes.

Claims

1. An electrode manufacturing method comprising: a coating step of forming an electrode mixture coating portion on an electrode sheet and an uncoated portion on which no electrode mixture is formed on the electrode sheet; a cutting step of cutting the electrode sheet into a plurality of unit electrode sheets along a cutting line; and a cutting-out step of cutting out the cut electrode sheet along a cutting-out line, wherein the uncoated portion includes: an electrode tab forming portion; and a folding portion formed parallel to a direction in which the cutting line is formed, wherein the cutting-out step is performed so that the folding portion is included in each of the plurality of unit electrode sheets, wherein the cutting line is formed on the coating portion and a position at which the coating portion is divided into two equal parts is located between the folding portions, the cutting-out line is formed in a straight line shape that passes through the coating portion and the folding portions and is perpendicular to the cutting line, and the folding portion is formed between the cutting line and the electrode tab forming portion.

2. The electrode production method according to claim 1, wherein The coating portion is continuously formed parallel to the direction in which the cutting line is formed.

3. The electrode production method according to claim 1, wherein The cutting step is a step of cutting the coating portion located between the folding portion and another folding portion adjacent to the folding portion.

4. The electrode manufacturing method according to claim 1, comprising a step of forming the uncoated portion so that a width of the electrode tab forming portion and a width of the folding portion are different from each other.

5. The electrode production method according to claim 1, wherein The cutting-out step includes: a cutting-out process for forming an electrode tab at the electrode tab forming portion; and a process of cutting out the unit electrode sheet along the cutting-out line to divide the unit electrode sheet.

6. The electrode production method according to claim 5, wherein The cutting-out process for forming the electrode tab and the process of cutting out the unit electrode sheet along the cutting-out line are simultaneously performed.

7. The electrode production method according to claim 1, wherein The electrode tab forming portions are formed at opposite side ends and a central portion of the electrode sheet, respectively.

8. The electrode production method according to claim 7, wherein The electrode sheet is cut into unit electrode sheets having two widths.

9. An electrode sheet for use in the electrode manufacturing method according to any one of claims 1 to 8, comprising: the coating portion on which an electrode mixture is formed to be coated; and the uncoated portion on which no electrode mixture is formed to be coated, wherein the uncoated portion includes: the electrode tab forming portion; and the folding portion formed parallel to a direction in which the cutting line is formed.

10. The electrode pad of claim 9, wherein, The coating portion, the electrode tab forming portion, and the folding portion are formed to be symmetrical about the cutting line.

11. The electrode pad of claim 10, wherein, The folding portion is an uncoated portion formed between the cutting line and the electrode tab forming portion.

12. The electrode pad of claim 10, wherein, First and second coating portions are formed on opposite sides of the folding portion, and wherein the first and second coating portions are formed to have the same size.

13. The electrode pad of claim 9, wherein, A width of the folding portion is greater than a thickness of the coating portion x π.

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