Electrode assembly, battery cell, battery pack, and electrode assembly manufacturing method

Abstract

This invention relates to an electrode assembly with a coated portion for short-circuit prevention, and more specifically, to an electrode assembly characterized by comprising: a positive electrode sheet, wherein a positive electrode connector protrudes from an outer end, and the lower portion of the current collector and the positive electrode connector is coated with a positive electrode mixture layer comprising a positive electrode active material; a negative electrode sheet, wherein a negative electrode connector protrudes from an outer end, and the lower portion of the current collector and the negative electrode connector is coated with a negative electrode mixture layer comprising a negative electrode active material; and a separator disposed between the positive electrode sheet and the negative electrode sheet, wherein a shoulder is formed on the negative electrode sheet, the shoulder extends a predetermined length in the horizontal direction and is coated with a negative electrode active material, and the shoulder is surrounded by the coated portion.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 2021-0109580, filed on August 19, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to an electrode assembly having a short-circuit prevention coating, and more specifically, to an electrode assembly having a short-circuit prevention coating configured to form a coating at a portion of the negative electrode sheet, configured to prevent short circuits caused by contact between the positive electrode mixture layer formed on the positive electrode terminal and the negative electrode sheet, thereby improving safety. Background Technology

[0003] In recent years, rechargeable batteries have been widely used as an energy source for wireless mobile devices. Furthermore, rechargeable batteries are gaining attention as an alternative to existing fossil fuel-powered gasoline and diesel vehicles, which contribute to air pollution, for use in electric and hybrid vehicles. As a result, due to the advantages of rechargeable batteries, their applications have become highly diversified, and it is expected that they will be used in even more fields and products in the future.

[0004] Based on the construction of the electrodes and electrolyte, secondary batteries can be classified as lithium-ion batteries, lithium-ion polymer batteries, or lithium polymer batteries. Among these, lithium polymer batteries, which have a low probability of electrolyte leakage and are easy to manufacture, are seeing increased use. Based on the shape of the battery casing, secondary batteries are typically classified as cylindrical batteries, prismatic batteries, or pouch batteries. Cylindrical batteries are configured such that the electrode assembly is housed in a cylindrical metal can, prismatic batteries are configured such that the electrode assembly is housed in a prismatic metal can, and pouch batteries are configured such that the electrode assembly is housed in a pouch-shaped casing made of aluminum laminates.

[0005] The electrode assembly installed in the battery casing is a power generation element, configured to have a structure including a positive electrode, a negative electrode, and a separator inserted between the positive and negative electrodes for charging and discharging. The electrode assembly is classified as a wound-type electrode assembly or a stacked cell assembly. The wound-type electrode assembly is configured to have an elongated positive electrode coated with active material and an elongated negative electrode coated with active material wound together with a separator inserted therebetween. The stacked cell assembly includes unit cells, each of which is configured to have a plurality of positive electrodes and a plurality of negative electrodes, each having a predetermined size, stacked sequentially with separators inserted therebetween.

[0006] Figure 1 This is a perspective view showing a conventional electrode plate.

[0007] Reference Figure 1A typical electrode plate includes an electrode current collector 10, an electrode active material layer 20, and an electrode connector 30.

[0008] The electrode connector 30 may include an extension region 31, an inclined portion 32, and an uncoated portion 33, and an electrode mixture layer of electrode active material is applied to the extension region 31 and the inclined portion 32.

[0009] During the manufacturing of the electrode assembly, the diaphragm may shrink due to heat during the heat-applied lamination process. As a result, the uncoated portion 33 or the extended area 31 and inclined portion 32 of the conventional electrode connector 30 may come into contact with the adjacent electrode plate, and thus a short circuit may occur.

[0010] Furthermore, since the extended region 31 and the inclined portion 32 are formed at the electrode connector 30, an overhang reversal phenomenon may occur, where the capacity ratio (N / P ratio) of the negative electrode and the positive electrode is reversed, depending on the formation characteristics of the mixed layer.

[0011] Existing technical documents

[0012] (Patent Document 1) Korean Patent Application Publication No. 2011-0060036 Summary of the Invention

[0013] Technical issues

[0014] The present invention was made in view of the above-mentioned problems. The object of the present invention is to provide an electrode assembly having a short-circuit prevention coating portion, which is configured such that the short-circuit prevention coating portion prevents contact between a positive electrode mixture layer formed on the underside of the positive electrode terminal and a negative electrode sheet located on the same vertical line as the positive electrode mixture layer.

[0015] Another object of the present invention is to provide an electrode assembly having a short-circuit prevention coating, which is configured to form a shoulder such that the shoulder extends from the negative electrode sheet at a predetermined length in the same vertical line as the positive electrode mixture layer formed on the underside of the positive electrode connector, thereby suppressing the occurrence of drooping reversal and thereby preventing lithium deposition.

[0016] Technical solution

[0017] An electrode assembly with a short-circuit prevention coating according to the present invention for achieving the above-mentioned objectives includes: a positive electrode sheet (100) having a positive electrode connector (110) and a positive electrode mixture layer (120), the positive electrode connector protruding from an outer end of one side of the positive electrode sheet, the positive electrode mixture layer including a positive electrode active material coated to the lower part of the positive electrode connector (110) and the current collector; and a negative electrode sheet (200) having a negative electrode connector (210) and a negative electrode mixture layer (220), the negative electrode connector protruding from an outer end of one side of the positive electrode sheet, the positive electrode mixture layer including a positive electrode active material coated to the lower part of the positive electrode connector (110) and the current collector; and a negative electrode sheet (200) having a negative electrode connector (210) and a negative electrode mixture layer (220), the negative electrode connector protruding from the lower end of one side of the positive electrode sheet, the positive electrode mixture layer including a positive electrode active material coated to the lower part of the positive electrode connector (110) and the current collector; and a negative electrode sheet (200) having a negative electrode connector (210) and a negative electrode mixture layer (220), the positive ... connector (110) and the current collector including a positive electrode active material coated to the lower part of the positive electrode connector (110) and the current collector including a positive electrode active material coated to the lower part of the positive electrode connector (110) and the current collector including a positive electrode active material coated to the lower part of the positive electrode connector (110) and the current collector including a positive electrode active material coated to the lower part of the positive electrode connector (110) and the current The outer end of one side of the negative electrode sheet protrudes, and the negative electrode mixture layer includes a negative electrode active material coated to the lower part of the negative electrode connector (210) and the current collector; and a separator (300) located between the positive electrode sheet (100) and the negative electrode sheet (200), wherein the negative electrode sheet (200) is provided with a shoulder (230) extending horizontally for a predetermined length, and the negative electrode active material is coated to the shoulder, and the shoulder (230) is surrounded by a coating portion (400).

[0018] Furthermore, in the electrode assembly according to the invention, the coating portion (400) may include: a pair of horizontal portions (410) arranged side by side; and a vertical portion (420) configured to connect the respective edges of the pair of horizontal portions (410) to each other.

[0019] Furthermore, in the electrode assembly according to the invention, the coating portion (400) may be made of an insulating material.

[0020] Furthermore, in the electrode assembly according to the invention, the shoulder (230) may be formed on the vertical extension line of the positive terminal (110).

[0021] Furthermore, in the electrode assembly according to the invention, the width (W1) of the shoulder 230 may be greater than the width (W2) of the positive terminal.

[0022] Furthermore, the present invention provides a battery cell including the electrode assembly.

[0023] Furthermore, the present invention provides a battery pack comprising at least one battery cell.

[0024] The electrode assembly manufacturing method according to the present invention includes the following steps: preparing a positive electrode sheet, a negative electrode sheet and a separator; slotting the negative electrode sheet to form a shoulder; forming a coating portion at the shoulder; and stacking the positive electrode sheet, the separator and the negative electrode sheet.

[0025] Furthermore, in the electrode assembly manufacturing method according to the present invention, in the step of stacking the positive electrode, the separator and the negative electrode, the stacking can be performed such that the center line of the shoulder and the center line of the positive electrode connector are on the same line.

[0026] Furthermore, in the electrode assembly manufacturing method according to the present invention, the electrode assembly can be configured to have a stacked structure, a Z-shaped structure, or a stacked folded structure.

[0027] Furthermore, in the electrode assembly manufacturing method according to the present invention, the electrode assembly is composed of a single cell such as a dual-cell or a full-cell, each of the dual-cell having a single electrode plate and an opposite outer electrode plate of the same polarity, and each of the full-cell having an opposite outer electrode plate of different polarities.

[0028] Technical effect

[0029] As is evident from the above description, the electrode assembly with short-circuit prevention coating according to the present invention has the advantage that the coating is disposed between the positive electrode mixture layer formed on the positive electrode connector and the shoulder of the negative electrode sheet to prevent contact between them, thereby improving safety.

[0030] Furthermore, the electrode assembly with short-circuit prevention coating according to the present invention has the advantage that the shoulder is formed to extend a predetermined length in a vertical line on the positive electrode mixture layer formed on the positive electrode terminal, thereby suppressing the occurrence of overhang reversal phenomenon and thus preventing lithium deposition. Attached Figure Description

[0031] Figure 1 This is a perspective view showing a conventional electrode plate.

[0032] Figure 2 This is a perspective view of an electrode assembly according to a preferred embodiment of the present invention.

[0033] Figure 3 It is along Figure 2 A cross-sectional view of the electrode assembly taken by the A-A' line.

[0034] Figure 4 This is a plan view of the positive and negative electrode plates of the electrode assembly according to a preferred embodiment of the present invention, excluding the diaphragm, as viewed from above. Detailed Implementation

[0035] 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 operational principles of the preferred embodiments of the present invention, detailed descriptions of known functions and configurations incorporated herein may obscure the subject matter of the invention, and will therefore be omitted.

[0036] Furthermore, the same reference numerals will be used throughout the drawings to refer to parts that perform similar functions or operations. Where a part is referred to as being connected to another part throughout the specification, this means not only that the part may be directly connected to the other part, but also that the part may be indirectly connected to the other part via yet another part. Moreover, including an element does not imply the exclusion of other elements, but rather means that such elements may be further included, unless otherwise specified.

[0037] The electrode assembly with a short-circuit prevention coating according to the present invention will be described below with reference to the accompanying drawings.

[0038] Figure 2 This is a perspective view of an electrode assembly according to a preferred embodiment of the present invention. Figure 3 It is along Figure 2 A cross-sectional view of the electrode assembly taken along line A-A'. Figure 4 This is a plan view of the positive and negative electrode plates of the electrode assembly according to a preferred embodiment of the present invention, excluding the diaphragm, as viewed from above.

[0039] Reference Figures 2 to 4 According to a preferred embodiment of the present invention, the electrode assembly includes a positive electrode 100, a negative electrode 200, a separator 300, and a coating portion 400.

[0040] The positive electrode connector 110 protrudes from the outer peripheral end of the positive electrode plate 100 by a predetermined length, and a positive electrode mixture layer 120 including positive electrode active material is applied to the lower part of the positive electrode connector 110 protruding by the predetermined length and the current collector.

[0041] Although the positive electrode mixture layer 120 applied to the lower part of the positive electrode connector 110 is in Figure 3 The positive electrode mixture layer 120, which is applied to the lower part of the positive electrode connector 110, may be a sliding shape with a predetermined curvature or a slope with a predetermined angle.

[0042] The negative electrode connector 210 protrudes from the outer peripheral end of one side of the negative electrode plate 200 by a predetermined length, and a negative electrode mixture layer 220 including negative electrode active material is applied to the lower part of the negative electrode connector 210 protruding by the predetermined length and the current collector.

[0043] Here, the negative electrode 200 has a larger area than the positive electrode 100 to suppress the occurrence of overhang reversal.

[0044] Furthermore, during the formation of the electrode assembly, a shoulder 230 extending for a predetermined length is formed at the portion of the negative electrode 200 that overlaps with the portion of the positive electrode 100 on which the positive electrode connector 110 is formed.

[0045] That is, the shoulder 230 can be formed at the negative electrode 200 located on the vertical extension line of the positive electrode connector 110, and can be formed at the portion of the negative electrode 200 corresponding to the lower part of the positive electrode connector 110 coated with the positive electrode mixture layer 120, thereby extending to a predetermined length while the negative electrode mixture layer 220 is coated. In this structure, the occurrence of drooping reversal can be suppressed.

[0046] When forming the negative electrode sheet 200, a negative electrode mixture layer 220 including the negative electrode active material is applied to the shoulder 230.

[0047] Furthermore, the shoulder 230 is formed such that the width W1 of the shoulder is greater than the width W2 of the positive electrode connector 110. In this case, the occurrence of overhang reversal caused by the positive electrode mixture layer 120 formed at the lower part of the positive electrode connector 110 can be suppressed, thereby preventing lithium deposition and improving safety.

[0048] In addition, the shoulder 230 may have a planar rectangular shape, and the protruding length of the shoulder 230 may be greater than the length of the positive electrode mixture layer 120 applied to the lower part of the positive electrode connector 110.

[0049] A separator 300 is located between the positive electrode 100 and the negative electrode 200, and serves to prevent short circuits between the positive electrode 100 and the negative electrode 200 while allowing only lithium ions to move through it. The separator is preferably made of any one of polyethylene, polypropylene, polyethylene / polypropylene bilayer, polyethylene / polypropylene / polypropylene trilayer, polypropylene / polypropylene / polypropylene trilayer, and organic fiber filter paper; however, the invention is not limited thereto.

[0050] The coating portion 400 includes a pair of horizontal portions 410 and a vertical portion 420, the pair of horizontal portions 410 being arranged side by side with a predetermined distance between them, and the vertical portion 420 being configured to connect the corresponding edges of the pair of horizontal portions 410 to each other.

[0051] The coating portion 400 is configured to wrap around the shoulder portion 230 to prevent short circuits.

[0052] As an example, during the manufacturing of the electrode assembly, after the lamination process in which heat is applied, the diaphragm may shrink due to heat, which may cause the positive terminal 110 and the shoulder 230 to come into contact with each other, thus potentially causing a short circuit.

[0053] However, since the coating portion 400 is provided in a shape that surrounds the shoulder portion 230, it is possible to prevent short circuits caused by contact between the positive terminal 110 and the shoulder portion 230.

[0054] The coating part 400 can be made of an insulating material such as rubber or silicone, and the material used for the coating part is not limited, as long as the coating part is arranged in a shape that wraps around the shoulder 230 to maintain an insulating state.

[0055] The present invention can provide a battery cell comprising an electrode assembly having at least one of the above features.

[0056] The present invention can provide a battery pack comprising at least one battery cell.

[0057] The electrode assembly manufacturing method according to a preferred embodiment of the present invention includes: a preparation step, wherein a positive electrode 100, a negative electrode 200 and a separator 300 are prepared; a grooving step, wherein a grooving step is performed on the negative electrode 200 to form a shoulder 230; a forming step, wherein a coating portion 400 is formed at the shoulder 230; and a stacking step, wherein the stacking step is performed on the positive electrode 100, the separator 300 and the negative electrode 200.

[0058] The preparation steps for the positive electrode, negative electrode and separator are to coat a mixture layer including electrode active materials onto a current collector to form the positive electrode and negative electrode and to prepare a separator configured to prevent short circuits between the positive electrode and negative electrode.

[0059] The step of slotting the negative electrode 200 to form the shoulder 230 is the step of slotting the negative electrode 200 to form the negative electrode connector 210 and the shoulder 230 spaced apart from the negative electrode connector 210 at a predetermined distance. The negative electrode 200 has a mixture layer including an electrode active material coated onto the current collector.

[0060] At this time, the positive electrode sheet 100 can be slotted to form the positive electrode connector 110, and the positive electrode mixture layer 120 can be applied to the lower end of the positive electrode connector 110.

[0061] In the step of forming the coating portion 400 at the shoulder 230, the shoulder 230 formed by slotting can be wrapped by the coating portion 400 made of insulating material to prevent short circuits caused by contact with the positive terminal 110.

[0062] The step of stacking the positive electrode 100, the separator 300 and the negative electrode 200 is the step of stacking the positive electrode 100, the separator 300 and the negative electrode 200 to form an electrode assembly.

[0063] Here, the stacking can be performed such that the center line of the shoulder 230 formed on the negative electrode 200 and the center line of the positive electrode connector 110 are on the same line. The reason for this is that if the stacking is performed such that the shoulder 230 and the positive electrode connector 110 are not aligned with each other, a drooping reversal may occur.

[0064] Electrode assemblies manufactured by the electrode assembly manufacturing method according to the present invention can be configured to have a stacked structure, a Z-shaped structure, or a stacked folded structure.

[0065] Here, the electrode assembly according to the invention can be a jelly-roll type cell assembly, a stacked type cell assembly, a stacked and folded type cell assembly, or a laminated and stacked type cell assembly. The jelly-roll type electrode assembly is configured to have a structure in which an elongated positive electrode and an elongated negative electrode are wound together with a separator inserted therebetween. The stacked type cell assembly includes unit cells, each of which is configured to have a structure in which a rectangular positive electrode and a rectangular negative electrode are stacked together with a separator inserted therebetween. The stacked and folded type cell assembly is configured to have a structure in which the unit cells are wound together using a long separation film. The laminated and stacked type cell assembly is configured to have a structure in which the unit cells are stacked together with a separator inserted therebetween and attached to each other. However, the invention is not limited thereto.

[0066] The sheet-type separation membrane forms a stacked folded cell assembly with the following structure: multiple unit cells are wound, and the outermost portion of the separation membrane located on the vertical extension line of the sliding portion of the outermost electrode of the separation membrane is bent with the same curvature as the sliding portion, thereby making close contact with the sliding portion. This prevents the deposition phenomenon caused by diffusion resistance in the space between the separation membrane and the sliding portion of the outermost electrode, which occurs in conventional electrode assemblies.

[0067] Furthermore, the electrode assembly manufactured by the electrode assembly manufacturing method according to the present invention can be composed of a single cell such as a dual cell or a full cell, each of the dual cells having a single electrode plate and an opposite outer electrode plate of the same polarity, and each of the full cells having an opposite outer electrode plate of different polarities.

[0068] Here, the dual-cell battery can be either a type A dual-cell battery or a type C dual-cell battery. The type A dual-cell battery is configured to have a positive electrode, a negative electrode, and a positive electrode stacked sequentially with a separator inserted between them. The type C dual-cell battery is configured to have a negative electrode, a positive electrode, and a negative electrode stacked sequentially with a separator inserted between them.

[0069] Those skilled in the art will understand that various applications and modifications can be made within the scope of this invention based on the above description.

[0070] Description of reference numerals in the attached figures

[0071] 100: Positive electrode plate

[0072] 110: Positive terminal connector

[0073] 120: Positive electrode mixture layer

[0074] 200: Negative electrode plate

[0075] 210: Negative terminal

[0076] 220: Negative electrode mixture layer

[0077] 230: Shoulders

[0078] 300: Diaphragm

[0079] 400: Coating section

[0080] 410: Horizontal section

[0081] 420: Vertical part

[0082] W1: Shoulder width

[0083] W2: Width of the positive terminal

Claims

1. An electrode assembly comprising: a positive electrode tab having a positive electrode joint protruding from an outer end of one side of the positive electrode tab and a positive electrode mixture layer including a positive electrode active material coated to a lower portion of the positive electrode joint and a current collector; a negative electrode tab having a negative electrode joint protruding from an outer end of one side of the negative electrode tab and a negative electrode mixture layer including a negative electrode active material coated to a lower portion of the negative electrode joint and a current collector; and a separator located between the positive electrode tab and the negative electrode tab, wherein the negative electrode tab is provided with a shoulder portion extending in a horizontal direction by a predetermined length and formed at a portion where the negative electrode tab overlaps with a portion of the positive electrode tab in which the positive electrode joint is formed, the negative electrode active material is coated to the shoulder portion, and the shoulder portion is surrounded by a coating portion.

2. The electrode assembly of claim 1, wherein, The coating portion includes: a pair of horizontal portions arranged side by side; and a vertical portion configured to connect respective edges of the pair of horizontal portions to each other.

3. The electrode assembly of claim 2, wherein, The coating portion is made of an insulating material.

4. The electrode assembly of claim 1, wherein, The shoulder portion is formed on a vertical extension line of the positive electrode joint.

5. The electrode assembly of claim 4, wherein, A width of the shoulder portion is greater than a width of the positive electrode joint. 6.A battery cell comprising the electrode assembly according to any one of claims 1 to 5. 7.A battery pack comprising at least one battery cell according to claim 6. 8.An electrode assembly manufacturing method for manufacturing the electrode assembly according to any one of claims 1 to 5, the electrode assembly manufacturing method comprising the steps of: preparing a positive electrode tab, a negative electrode tab, and a separator; slitting the negative electrode tab to form a shoulder portion; forming a coating portion at the shoulder portion; and stacking the positive electrode tab, the separator, and the negative electrode tab. In the step of stacking the positive electrode tab, the separator, and the negative electrode tab, the stacking is performed such that a center line of the shoulder portion and a center line of a positive electrode joint of the positive electrode tab are located on the same line.

9. The electrode assembly production method according to claim 8, wherein The electrode assembly is configured to have a stacked type structure, a Z-shaped type structure, or a stacked and folded type structure.

10. The electrode assembly production method according to claim 8, wherein The electrode assembly is constituted by unit cells of a double cell each having a single plate of the same polarity and an opposite outer plate, or a full cell each having opposite outer plates of different polarities.

11. The electrode assembly production method according to claim 8, wherein The coating portion includes:

12. The electrode assembly production method according to claim 8, wherein a pair of horizontal portions arranged side by side; and a vertical portion configured to connect respective edges of the pair of horizontal portions to each other. The coating portion is made of an insulating material.

13. The electrode assembly production method according to claim 8, wherein The shoulder portion is formed on a vertical extension line of the positive electrode joint.

14. The electrode assembly production method according to claim 8, wherein A width of the shoulder portion is greater than a width of the positive electrode joint.

15. The electrode assembly production method according to claim 14, wherein ​

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