Electrode assembly including positive electrode having insulating coating and method for manufacturing same

Abstract

The invention relates to an electrode assembly including a positive electrode having an insulating coating and a method of manufacturing the same. The present invention relates to an electrode assembly including a positive electrode having an insulating coating layer, and a method for manufacturing the same, and more particularly, to an electrode assembly including a positive electrode having an insulating coating layer, which is characterized by including at least one first single cell and a second single cell stacked on the uppermost portion of the first single cell, and the second single cell having an insulating coating layer, and to a method for manufacturing the same.

Description

Technical Field

[0001] This application claims the benefit of priority to Korean Patent Application No. 2023-0056601, filed on April 28, 2023, and Korean Patent Application No. 2024-0021296, filed on February 14, 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0002] The present invention relates to an electrode assembly including a positive electrode having an insulating coating and a method for manufacturing the same, and more particularly, to an electrode assembly including a positive electrode having an insulating coating and a method for manufacturing the same, which can increase energy density while performing a stable manufacturing process. Background Art

[0003] As alternative energy has been developed in recent years due to air pollution and energy depletion caused by the use of fossil fuels, the demand for secondary batteries that can store the generated electrical energy has also increased. Rechargeable and dischargeable secondary batteries are closely related to daily life. For example, secondary batteries are used in mobile devices, electric vehicles, and hybrid electric vehicles.

[0004] Due to the increase in the use of mobile devices, the increase in the complexity of mobile devices, and the development of electric vehicles, the required capacity of lithium secondary batteries used as energy sources for various electronic devices is inevitably used in modern society. In order to meet the needs of users, a plurality of battery cells are provided in small devices, and a battery module including a plurality of battery cells electrically connected to each other or a battery pack including a plurality of battery modules is used in vehicles, etc.

[0005] In addition, if Figure 1 As shown, Figure 1 It is a cross-sectional view of a conventional electrode stack. The electrode assembly housed in a battery cell shell is typically configured so that a plurality of monocells M and a half-cell H are stacked in sequence. In each monocell M, a separator 30, a negative electrode 20, a separator 30 and a positive electrode 10 are arranged in sequence. In a half-cell H, a separator 30, a negative electrode 20 and a separator 30 are arranged in sequence.

[0006] However, the half-cell located at the uppermost end of the electrode assembly is thinner than each single cell because the half-cell includes a separator, a negative electrode and a separator, making it inconvenient to transport or stack the half-cell, which may result in reduced efficiency of the production process or product defects.

[0007] Furthermore, after stacking a plurality of single cells and a half cell, it is necessary to wrap the electrode assembly with a separate insulating member such as a separator in order to ensure insulation from the battery cell case.

[0008] (Prior art literature)

[0009] (Patent Document 1) Korean Patent Application Publication No. 2015-0100017 Summary of the invention

[0010] Technical issues

[0011] The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrode assembly including a positive electrode having an insulating coating layer and a method of manufacturing the electrode assembly capable of performing a stable production process.

[0012] Another object of the present invention is to provide an electrode assembly including a positive electrode having an insulating coating layer and a method of manufacturing the electrode assembly capable of improving production efficiency by reducing the number of unit production processes.

[0013] Technical Solution

[0014] The electrode assembly according to the present invention for achieving the above-mentioned purpose comprises at least one first single cell and a second single cell, wherein the second single cell is stacked on the uppermost end of the first single cell, wherein the second single cell has an insulating coating.

[0015] Furthermore, in the electrode assembly according to the present invention, the insulating coating layer may be made of any one of polyethylene terephthalate (PET), polypropylene (PP), and ceramic.

[0016] Furthermore, in the electrode assembly according to the present invention, the insulating coating layer may be made of ceramic.

[0017] Furthermore, in the electrode assembly according to the present invention, the second single cell is configured such that a second separator, a second negative electrode, a second separator, and a second positive electrode are sequentially stacked from below, and the insulating coating may be provided on the second positive electrode.

[0018] Furthermore, in the electrode assembly according to the present invention, the second positive electrode may be configured such that a second positive electrode active material, a second positive electrode current collector, and an insulating coating layer are sequentially stacked from below.

[0019] In addition, in the electrode assembly according to the present invention, the second single cell may have a thickness of 150 μm to 250 μm.

[0020] In addition, in the electrode assembly according to the present invention, the insulating coating layer may have a thickness of 10 μm to 20 μm.

[0021] In addition, in the electrode assembly according to the present invention, the first single cell can be configured so that a first separator, a first negative electrode, a first separator and a first positive electrode are stacked in sequence from below, and at least one of the first negative electrode and the second negative electrode configured to store lithium ions may include silicon.

[0022] In addition, in the electrode assembly according to the present invention, the silicon may be included to account for 95 wt % or more based on the negative electrode active material.

[0023] In addition, in the electrode assembly according to the present invention, the first single cell may have a thickness of 150 μm to 250 μm.

[0024] In addition, in the electrode assembly according to the present invention, the first single cell may have a thickness of 150 μm to 200 μm.

[0025] In addition, the present invention provides a battery cell including the electrode assembly.

[0026] In addition, the electrode assembly manufacturing method according to the present invention includes the following steps: a first step of preparing at least one first single cell and a second single cell; and a second step of stacking the at least one first single cell and the second single cell in sequence from below, wherein the first single cell is configured so that a first separator, a first negative electrode, a first separator and a first positive electrode are stacked in sequence from below, the second single cell is configured so that a second separator, a second negative electrode, a second separator and a second positive electrode are stacked in sequence from below, and the second positive electrode includes a second positive electrode current collector, a second positive electrode active material arranged on the lower surface of the second positive electrode current collector, and an insulating coating arranged on the upper surface of the second positive electrode current collector.

[0027] Furthermore, in the method of manufacturing an electrode assembly according to the present invention, the insulating coating layer may be made of ceramic.

[0028] Furthermore, in the electrode assembly manufacturing method according to the present invention, at least one of the first negative electrode and the second negative electrode may include silicon.

[0029] Beneficial effects

[0030] As is apparent from the above description, the insulating coating is located at the uppermost end of the second positive electrode of the second single cell constituting the electrode assembly according to the present invention, thereby maintaining insulation between the electrode assembly and the battery case in the absence of a separate separator configured to cover the entire electrode assembly, which helps to simplify the production process and reduce manufacturing costs.

[0031] In addition, when the insulating coating located at the uppermost end of the second positive electrode of the second single cell constituting the electrode assembly according to the present invention is made of ceramic, the phenomenon of the second positive electrode or the second single cell being bent or sagging can be minimized, which facilitates the transfer or stacking of the second positive electrode or the second single cell.

[0032] In addition, the silicon-based negative electrode active material is mainly used as the negative electrode active material of the electrode assembly according to the present invention, and thus the storage amount of lithium ions can be increased, which improves the energy density. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a cross-sectional view of a conventional electrode stack.

[0034] Figure 2 is an exploded cross-sectional view of an electrode assembly according to a preferred embodiment of the present invention.

[0035] Figure 3 is an enlarged cross-sectional view of a first single cell according to a preferred embodiment of the present invention.

[0036] Figure 4 is an enlarged cross-sectional view of a second single cell according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0037] Now, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that the preferred embodiments of the present invention can be easily implemented by those of ordinary skill in the art to which the present invention belongs. However, when describing the operating principle of the preferred embodiments of the present invention in detail, when the detailed description of the known functions and configurations incorporated herein may obscure the subject matter of the present invention, the detailed description will be omitted.

[0038] In addition, the same reference numerals will be used throughout the drawings to refer to components that perform similar functions or operations. Throughout the specification, if a component is said to be connected to another component, not only can the component be directly connected to the other component, but the component can also be indirectly connected to the other component via yet another component. In addition, including a certain element does not mean excluding other elements, unless otherwise specified, otherwise it means that such elements can be further included.

[0039] Hereinafter, an electrode assembly including a positive electrode having an insulating coating layer and a method of manufacturing the same according to the present invention will be described with reference to the accompanying drawings.

[0040] Figure 2 is an exploded cross-sectional view of an electrode assembly according to a preferred embodiment of the present invention. Figure 3 is an enlarged cross-sectional view of a first single cell according to a preferred embodiment of the present invention, and Figure 4 is an enlarged cross-sectional view of a second single cell according to a preferred embodiment of the present invention.

[0041] refer to Figures 2 to 4 , the electrode assembly according to the present invention includes at least one first single cell 100 and one second single cell 200 , wherein the first single cell 100 is located at the bottom, and the second single cell 200 is disposed at the uppermost end.

[0042] First, the first single cell 100 is substantially the same in configuration as a commonly known single cell including two separators, a negative electrode, and a positive electrode, that is, a first separator 110 , a first negative electrode 120 , a first separator 110 , and a first positive electrode 130 are sequentially stacked from below.

[0043] The first separator 110 is respectively located on the lower surface of the first negative electrode 120 and between the upper surface of the first negative electrode 120 and the lower surface of the first positive electrode 130 to prevent a short circuit between the first negative electrode 120 and the first positive electrode 130 and allow only migration of lithium ions.

[0044] The first separator 110 is preferably made of any one selected from polyethylene, polypropylene, polyethylene / polypropylene double layer, polyethylene / polypropylene / polyethylene triple layer, polyethylene / polyethylene / polypropylene triple layer, and organic fiber filter paper; however, the present invention is not limited thereto.

[0045] The first negative electrode 120 includes a first negative current collector 121 and a first negative active material 122 applied to each of the lower and upper surfaces of the first negative current collector 121 .

[0046] The first negative electrode current collector 121 is generally manufactured to have a thickness of 3 μm to 500 μm. The first negative electrode current collector 121 is not particularly limited as long as the first negative electrode current collector exhibits high electrical conductivity and the first negative electrode current collector does not cause any chemical changes in the battery to which the first negative electrode current collector is applied. For example, the first negative electrode current collector may be made of copper, stainless steel, aluminum, nickel, titanium or sintered carbon. Alternatively, the first negative electrode current collector may be made of copper or stainless steel, the surface of which is treated with carbon, nickel, titanium or silver or aluminum-cadmium alloy.

[0047] In addition, the first negative electrode current collector may have a micro-scale uneven pattern formed on its surface to increase the binding force of the negative electrode active material. The first negative electrode current collector may be configured in any of various forms such as a film, a sheet, a foil, a net, a porous body, a foam body, and a non-woven fabric body.

[0048] The first negative electrode active material 122 configured to store lithium ions may include a silicon-based negative electrode active material and / or lithium metal, including graphite, or most of the negative electrode active material may be composed of silicon. For example, based on the negative electrode active material, silicon is preferably included to account for 95 weight % (wt%) or more, and more preferably 99 weight %.

[0049] The silicon-based negative electrode active material may be at least one of Si, SiO, SiO2 and a nano-silicon composite material, the nano-silicon composite material may be any one of a silicon alloy, and the metal element included in the silicon alloy may be at least one of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te and Po.

[0050] Of course, the first negative electrode active material 122 may be applied to the first negative electrode collector 121 in a state in which a conductive agent and a binder are further mixed with the first negative electrode active material.

[0051] The conductive agent is a component configured to further improve the conductivity of the negative electrode active material, and carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black or thermal black may be used in a predetermined proportion; conductive fibers such as carbon fibers or metal fibers; metal powders such as carbon fluoride powders, aluminum powders or nickel powders; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive materials such as polyphenylene derivatives.

[0052] The binder is a component that assists the bonding between the negative electrode active material and the conductive agent and is bonded to the current collector, and may include at least one selected from the group consisting of styrene butadiene rubber (SBR), acrylonitrile butadiene rubber, acrylic rubber, butyl rubber, fluororubber, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl alcohol (PVA), polyacrylic acid (PAA), polyethylene glycol (PEG), polyacrylonitrile (PAN) and polyacrylamide (PAM).

[0053] When a silicon-based negative electrode active material is used to store lithium ions, as described above, more lithium ions can be stored per unit area than conventionally used graphite-based negative electrode active materials, thereby improving energy density, which can help reduce the overall volume of the electrode assembly.

[0054] The first positive electrode 130 includes a first positive current collector 131 and a first positive active material 132 applied to each of a lower surface and an upper surface of the first positive current collector 131 .

[0055] The first positive current collector 131 may generally have a thickness of 3 μm to 500 μm. The first positive current collector is not particularly limited as long as the first positive current collector exhibits high conductivity and the first positive current collector does not cause any chemical changes in the battery. For example, the first positive current collector may be made of stainless steel, aluminum, nickel, titanium or sintered carbon. Alternatively, the first positive current collector may be made of aluminum or stainless steel, the surface of which is treated with carbon, nickel, titanium or silver. In addition, the first positive current collector may have a microscale uneven pattern formed on its surface to increase the adhesion of the positive active material, or the first positive current collector may be configured in any of various forms such as a film, a sheet, a foil, a mesh, a porous body, a foam body and a non-woven fabric body.

[0056] Layered compounds such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or compounds substituted with one or more transition metals; 1+x Mn 2-x Lithium manganese oxide represented by LiMnO4 (where x=0 to 0.33) or lithium manganese oxide such as LiMnO3, LiMn2O3 or LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxide such as LiV3O8, V2O5 or Cu2V2O7; 1-x M x Ni-localized lithium nickel oxide represented by O2 (wherein M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); represented by the chemical formula LiMn 2-x M x Lithium manganese composite oxides represented by the formula LiMnMO (wherein M=Co, Ni, Fe, Cr, Zn or Ta, and x=0.01 to 0.1) or LiMn2O4 (wherein M=Fe, Co, Ni, Cu or Zn); disulfide; Fe2(MoO4)3; or LiNi x Mn 2-x O 4 (0.01≦x≦0.6) may be used as the first positive electrode active material 132 .

[0057] In addition, the first positive electrode active material 132 may be mixed with a conductive agent and a binder, and a filler may be further added as needed.

[0058] The conductive agent is generally added so that the conductive agent accounts for 1 wt % to 50 wt % based on the total weight of the mixture including the first positive electrode active material 132. The conductive agent is not particularly limited as long as the conductive agent exhibits high conductivity while not causing any chemical changes in the battery to which the conductive agent is applied. For example, graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, or thermal black; conductive fibers such as carbon fibers or metal fibers; metal powders such as carbon fluoride powders, aluminum powders, or nickel powders; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive materials such as polyphenylene derivatives can be used as the conductive agent.

[0059] The binder is a component that assists bonding between the first positive active material 132 and the conductive agent and bonding with the current collector, and is generally added in an amount of 1 wt % to 50 wt % based on the total weight of the mixture including the first positive active material 132. As examples of the binder, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, and various copolymers can be used.

[0060] The thickness of the first single cell 100 including the above-described configuration may be 400 μm or less, preferably 150 μm to 250 μm, and more preferably 150 μm to 200 μm.

[0061] The second single cell 200 is similar in structure to the first single cell 100 , and is configured such that a second separator 210 , a second negative electrode 220 , a second separator 210 , and a second positive electrode 230 are sequentially stacked from below.

[0062] Here, the second separator 210 may be the same as the first separator 110 of the first single cell 100 , and the second negative electrode 220 may have the same configuration as the above-described first negative electrode 120 , and thus repeated descriptions thereof will be omitted.

[0063] The second positive electrode 230 includes a second positive current collector 231 , a second positive active material 232 applied to a lower surface of the second positive current collector 231 , and an insulating coating 233 on an upper surface of the second positive current collector 231 .

[0064] The second positive electrode current collector 231 and the second positive electrode active material 232 have the same configurations as the first positive electrode current collector 131 and the first positive electrode active material 132 , respectively.

[0065] The insulating coating layer 233 located on the upper surface of the second positive current collector 231 (ie, the uppermost end of the electrode assembly) may be made of an insulating material.

[0066] The material of the insulating coating 233 is preferably at least one selected from polyethylene terephthalate (PET), polypropylene (PP), and ceramics, and more preferably polypropylene (PP) or ceramics is used.

[0067] In particular, it is most preferred that the insulating coating 233 is made of ceramic. The reason is that the mechanical strength of the second positive electrode 230 is improved due to the formation of the ceramic coating, and further, the second positive electrode can be maintained in a certain rigid state, which facilitates the transfer or lamination of the second positive electrode 230.

[0068] Here, the thickness of the insulating coating layer 233 is preferably 10 μm to 20 μm.

[0069] When the surface of the electrode assembly exposed to the outside while located at the uppermost end of the electrode assembly is formed as the insulating coating layer 233 , as described above, insulation between the electrode assembly and the battery case can be maintained without a separate separator configured to cover the entire electrode assembly.

[0070] In addition, the half-cell including the separator, the negative electrode and the separator is located at the uppermost end of the conventional electrode assembly, while in the present invention, the second positive electrode having the second positive electrode active material applied to the lower surface of the second positive electrode collector and the insulating coating disposed on the upper surface of the second positive electrode collector is further disposed on the upper surface of the separator. Therefore, compared with the conventional half-cell, the thickness of the half-cell is increased, thereby stabilizing the process (such as transfer or lamination) of the half-cell.

[0071] In addition, the thickness of the second single cell 200 including the above-described configuration may be 400 μm or less, preferably 150 μm to 250 μm, and more preferably 150 μm to less than 200 μm.

[0072] The method for manufacturing the electrode assembly having the above-described configuration according to the present invention includes a first step of preparing at least one first single cell 100 and one second single cell 200 and a second step of sequentially stacking the at least one first single cell 100 and the second single cell 200 from below.

[0073] As described above, the first single cell 100 has a structure in which the first separator 110, the first negative electrode 120, the first separator 110 and the first positive electrode 130 are stacked in sequence from below, and the second single cell 200 has a structure in which the second separator 210, the second negative electrode 220, the second separator 210 and the second positive electrode 230 are stacked in sequence from below.

[0074] The detailed configurations of the first separator 110 , the first negative electrode 120 , the first separator 110 and the first positive electrode 130 constituting the first single cell 100 and the second separator 210 , the second negative electrode 220 , the second separator 210 and the second positive electrode 230 constituting the second single cell 200 are as described above, so repeated descriptions thereof will be omitted.

[0075] The present invention provides a pouch-shaped secondary battery having an electrode assembly accommodated therein and a battery module or a battery pack including the secondary battery.

[0076] Those skilled in the art to which the present invention pertains will appreciate that, based on the above description, various applications and modifications are possible within the category of the present invention.

[0077] (Description of Reference Numerals)

[0078] 100: The first single cell

[0079] 110: First diaphragm

[0080] 120: First negative electrode

[0081] 121: first negative electrode current collector 122: first negative electrode active material

[0082] 130: First positive electrode

[0083] 131: first positive electrode current collector 132: first positive electrode active material

[0084] 200: Second single cell

[0085] 210: Second diaphragm

[0086] 220: Second negative pole

[0087] 221: Second negative electrode current collector 222: Second negative electrode active material

[0088] 230: Second positive electrode

[0089] 231: Second positive electrode current collector 232: Second positive electrode active material

[0090] 233: Insulation coating

Claims

1. An electrode assembly, comprising: at least one first single battery cell; as well as A second single cell, wherein the second single cell is stacked on the uppermost end of the first single cell, Wherein, the second single cell has an insulating coating.

2. The electrode assembly according to claim 1, wherein: The insulating coating is made of any one of polyethylene terephthalate (PET), polypropylene (PP) and ceramic.

3. The electrode assembly according to claim 2, wherein: The insulating coating is made of ceramic.

4. The electrode assembly according to claim 2, wherein: The second single cell is configured such that a second separator, a second negative electrode, a second separator, and a second positive electrode are sequentially stacked from below, and the insulating coating is provided on the second positive electrode.

5. The electrode assembly according to claim 4, wherein: The second positive electrode is configured such that a second positive electrode active material, a second positive electrode current collector, and an insulating coating layer are sequentially stacked from below.

6. The electrode assembly according to claim 3, wherein: The second single cell has a thickness of 150 μm to 250 μm.

7. The electrode assembly according to claim 6, wherein: The insulating coating layer has a thickness of 10 μm to 20 μm.

8. The electrode assembly according to claim 4, wherein: The first single cell is configured such that a first separator, a first negative electrode, a first separator, and a first positive electrode are sequentially stacked from below, and at least one of the first negative electrode and the second negative electrode configured to store lithium ions includes silicon.

9. The electrode assembly according to claim 8, wherein: The silicon is included to account for 95 wt % or more based on the negative electrode active material.

10. The electrode assembly according to claim 8, wherein: The first single cell has a thickness of 150 μm to 250 μm.

11. The electrode assembly according to claim 10, wherein: The first single cell has a thickness of 150 μm to 200 μm.

12. A battery cell comprising the electrode assembly according to any one of claims 1 to 11.

13. A method for manufacturing an electrode assembly, the method comprising the following steps: A first step of preparing at least one first single cell and a second single cell; and A second step of stacking the at least one first single cell and the second single cell in sequence from below, wherein: The first single cell is configured such that a first separator, a first negative electrode, a first separator and a first positive electrode are stacked in sequence from the bottom. The second single cell is configured such that a second separator, a second negative electrode, a second separator and a second positive electrode are sequentially stacked from below, and The second positive electrode includes a second positive electrode current collector, a second positive electrode active material disposed on a lower surface of the second positive electrode current collector, and an insulating coating disposed on an upper surface of the second positive electrode current collector.

14. The method for manufacturing an electrode assembly according to claim 13, wherein: The insulating coating is made of ceramic.

15. The method for manufacturing an electrode assembly according to claim 14, wherein: At least one of the first cathode and the second cathode includes silicon.

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