Electrode assembly including a positive electrode provided with an insulating coating layer and method for manufacturing the same

Abstract

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 specifically relates to an electrode assembly including one or more first monocells; and a second monocell laminated on the uppermost part of the first monocell; wherein the second monocell is provided with an insulating coating layer, and a method for manufacturing the same.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0056601 filed on April 28, 2023, and Korean Patent Application No. 10-2024-0021296 filed on February 14, 2024, and all the contents disclosed in the documents of the Korean patent applications are included as part of this specification.

[0002] 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 specifically, to an electrode assembly including a positive electrode having an insulating coating layer and a method for manufacturing the same, which enable a stable manufacturing process and can increase the energy density.

Background Art

[0003] In recent years, there has been an increasing demand for secondary batteries that can store electrical energy produced by developing alternative energy due to air pollution caused by the use of fossil fuels and energy depletion. Secondary batteries that can be charged and discharged are closely used in daily life, such as being used in mobile devices, electric vehicles, hybrid electric vehicles, etc.

[0004] Secondary batteries used as an energy source for various essential electronic devices in modern society are increasing in capacity required by the increasing use and complexity of mobile devices and the development of electric vehicles, etc. To meet the needs of users, a large number of battery cells are arranged in small devices, but in vehicles, etc., a battery module that electrically connects a large number of battery cells or a battery pack having a large number of such battery modules is used.

[0005] On the other hand, as shown in FIG. 1 which is a cross-sectional view of an electrode stack part according to the prior art, an electrode assembly accommodated in a cell case is generally configured by sequentially laminating a plurality of monocells M arranged in the order of a separator 30, a negative electrode 20, a separator 30, and a positive electrode 10, and a single half-cell H arranged in the order of a separator 30, a negative electrode 20, and a separator 30.

[0006] However, the half cell located at the uppermost end of the electrode assembly is composed of a separation membrane, a negative electrode, and a separation membrane, and is thinner than a single cell, so it is not easy to transport or stack, which is likely to lead to a decrease in the efficiency of the production process and defective products.

[0007] In addition, after stacking a large number of single cells and one half cell, in order to ensure insulation with the cell case, a step of covering the electrode assembly with a separate insulating member such as a separation membrane is necessarily accompanied.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] In order to solve the above problems, an object of the present invention is to provide an electrode assembly including a positive electrode provided with an insulating coating layer capable of a stable production process and a method for manufacturing the same.

[0010] In addition, an object of the present invention is to provide an electrode assembly including a positive electrode provided with an insulating coating layer capable of reducing the unit production process and increasing the production efficiency and a method for manufacturing the same.

Means for Solving the Problems

[0011] The electrode assembly according to the present invention for achieving the above object includes one or more first single cells and a second single cell stacked on the uppermost part of the first single cell, and the second single cell is characterized in that it is provided with an insulating coating layer.

[0012] Further, in the electrode assembly according to the present invention, the insulating coating layer is characterized by being any one or more of polyethylene terephthalate (PET), polypropylene (PP), and ceramic.

[0013] Further, in the electrode assembly according to the present invention, the insulating coating layer is characterized by being ceramic.

[0014] Further, in the electrode assembly according to the present invention, the second monocell is laminated in the order of a second separator, a second negative electrode, a second separator, and a second positive electrode from the bottom, and the insulating coating layer is provided on the second positive electrode.

[0015] Further, in the electrode assembly according to the present invention, the second positive electrode is characterized by being laminated in the order of a second positive electrode active material, a second positive electrode current collector, and the insulating coating layer from the bottom.

[0016] Further, in the electrode assembly according to the present invention, the thickness of the second monocell is in the range of 150 μm to 250 μm.

[0017] Further, in the electrode assembly according to the present invention, the thickness of the insulating coating layer is in the range of 10 μm to 20 μm.

[0018] Further, in the electrode assembly according to the present invention, the first monocell is laminated in the order of a first separator, a first negative electrode, a first separator, and a first positive electrode from the bottom, and any one or more of the first negative electrode and the second negative electrode for storing lithium ions contains silicon (Silicon).

[0019] Further, in the electrode assembly according to the present invention, the silicon is characterized by being 95% by weight or more based on the negative electrode active material.

[0020] Further, in the electrode assembly according to the present invention, the thickness of the first monocell is in the range of 150 μm to 250 μm.

[0021] In the electrode assembly according to the present invention, the thickness of the first monocell is in the range of 150 μm to 200 μm.

[0022] Further, the present invention can be a battery cell including the above-described electrode assembly.

[0023] The method for manufacturing an electrode assembly according to the present invention includes: a first step of preparing one or more first monocells and a second monocell; and a second step of sequentially laminating one or more first monocells and one second monocell from below. The first monocell is laminated in the order of a first separator, a first negative electrode, a first separator, and a first positive electrode from below, the second monocell is laminated in the order of a second separator, a second negative electrode, a second separator, and a second positive electrode from below, and the second positive electrode is composed of a second positive electrode current collector, a second positive electrode active material on the lower surface of the second positive electrode current collector, and an insulating coating layer on the upper surface of the second positive electrode current collector.

[0024] In the method for manufacturing an electrode assembly according to the present invention, the insulating coating layer is made of ceramic.

[0025] In the method for manufacturing an electrode assembly according to the present invention, one or more of the first negative electrode and the second negative electrode contain silicon.

Advantages of the Invention

[0026] As described above, an insulating coating layer is located at the uppermost part of the second positive electrode constituting the second monocell of the electrode assembly according to the present invention. This has the advantage that it can maintain the insulating state between the electrode assembly and the battery case even without a separate separator covering the entire electrode assembly, contributing to the simplification of the production process and the reduction of manufacturing costs.

[0027] In addition, when the uppermost insulating coating layer of the second positive electrode constituting the second monocell of the electrode assembly according to the present invention is made of ceramic, the phenomenon that the second positive electrode or the second monocell bends or sags can be minimized, so there is an advantage that the transportation and stacking of these second positive electrodes and second monocells are very easy.

[0028] Furthermore, since the negative electrode active material of the electrode assembly according to the present invention is mainly composed of a silicon-based negative electrode active material, there is an advantage that the storage amount of lithium ions can be increased and the energy density is improved.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0030] Hereinafter, with reference to the accompanying drawings, embodiments that can be easily implemented by those having ordinary knowledge in the technical field to which the present invention pertains will be described in detail. However, when it is determined that a detailed description of related known functions or configurations may obscure the gist of the present invention in the detailed description of the operating principle of a preferred embodiment of the present invention, the detailed description thereof will be omitted.

[0031] In addition, the same reference numerals are used for functionally and operationally similar parts throughout the drawings. Throughout the specification, when one part is described as being connected to another part, this includes not only the case where they are directly connected, but also the case where they are indirectly connected with other elements interposed therebetween. Further, including one component means, unless otherwise stated to the contrary, not excluding other components, but rather may further include other components.

[0032] Hereinafter, an electrode assembly including a positive electrode provided with an insulating coating layer according to the present invention and a method for manufacturing the same will be described with reference to the accompanying drawings.

[0033] FIG. 2 is an exploded cross-sectional view of an electrode assembly according to a preferred embodiment of the present invention, FIG. 3 is an enlarged cross-sectional view of a first monocell according to a preferred embodiment of the present invention, and FIG. 4 is an enlarged cross-sectional view of a second monocell according to a preferred embodiment of the present invention.

[0034] Referring to FIGS. 2 to 4, the electrode assembly according to the present invention includes one or more first monocells 100 and one second monocell 200. At this time, the first monocell 100 is located on the lower side, and the second monocell 200 is disposed on the upper outermost periphery.

[0035] First, the first monocell 100 has substantially the same configuration as a generally known monocell composed of two separator membranes, one negative electrode, and one positive electrode. That is, the first monocell 100 is laminated in the order of a first separator membrane 110, a first negative electrode 120, a first separator membrane 110, and a first positive electrode 130 from the bottom.

[0036] The first separator membrane 110 is located between 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, and serves to prevent a short between the first negative electrode 120 and the first positive electrode 130 and to allow only the movement of lithium ions.

[0037] The material of such a first separation membrane 110 is preferably any one selected from polyethylene, polypropylene, polyethylene / polypropylene bilayer, polyethylene / polypropylene / polyethylene trilayer, polypropylene / polyethylene / polypropylene trilayer, and organic fiber filter paper, but is not limited thereto.

[0038] The first negative electrode 120 includes a first negative electrode current collector 121 and a first negative electrode active material 122 applied to the lower surface and the upper surface of the first negative electrode current collector 121, respectively.

[0039] The first negative electrode current collector 121 is generally made with a thickness of 3 μm to 500 μm. Such a first negative electrode current collector 121 is not particularly limited as long as it does not induce a chemical change in the battery and has conductivity. Examples of the first negative electrode current collector 121 include copper, stainless steel, aluminum, nickel, titanium, fired carbon, and those with a surface treatment of carbon, nickel, titanium, silver, etc. on the surface of copper or stainless steel, and aluminum-cadmium alloy, etc. can be used.

[0040] In addition, the first negative electrode current collector 121 can form fine irregularities on its surface to strengthen the binding force of the negative electrode active material, and can be used in various forms such as films, sheets, foils, nets, porous bodies, foams, non-woven bodies, etc.

[0041] The first negative electrode active material 122 for storing lithium ions can include graphite, silicon-based and / or lithium metal, or most of the negative electrode active material can be made of silicon. For example, silicon is preferably 95% by weight or more, more preferably 99% by weight, based on the negative electrode active material.

[0042] The silicon-based negative electrode active material is Si, SiO, SiO 2and any one or more of the nanosilicon composites. The nanosilicon composite can be any one of the silicon alloys. Further, the metal element contained in the silicon alloy can be at least any 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.

[0043] Of course, a conductive material and a binder can be additionally mixed with the first negative electrode active material 122, and these can be coated on the first negative electrode current collector 121.

[0044] The conductive material is a component for further improving the conductivity of the negative electrode active material. As the conductive material, carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, etc. can be used in a certain ratio.

[0045] The binder is a component that aids in binding the negative electrode active material, conductive material, etc. and binding to the current collector, and can include at least one selected from the group consisting of styrene butadiene rubber (SBR), acrylonitrile butadiene rubber, acrylic rubber, butyl rubber, fluoro rubber, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl alcohol (PVA), polyacrylic acid (PAA), polyethylene glycol (PEG), polyacrylonitrile (PAN), and polyacrylamide (PAM).

[0046] When composed of a silicon-based negative electrode active material for storing lithium ions in this way, more lithium ions per unit area can be stored than the graphite-based negative electrode active material used conventionally, so the energy density is improved, which has the advantage of contributing to reducing the overall volume of the electrode assembly.

[0047] The first positive electrode 130 is composed of a first positive electrode current collector 131 and a first positive electrode active material 132 applied to the upper and lower surfaces of the first positive electrode current collector 131, respectively.

[0048] The first positive electrode current collector 131 can generally have a thickness of 3 μm to 500 μm. As long as it does not induce chemical changes in the battery and has high conductivity, there is no particular limitation. Examples of the first positive electrode current collector 131 include stainless steel, aluminum, nickel, titanium, fired carbon, or those obtained by surface treatment of the surface of aluminum or stainless steel with carbon, nickel, titanium, silver, etc. In addition, in order to enhance the adhesive force of the positive electrode active material, fine irregularities can be formed on the surface, or various forms such as films, sheets, foils, nets, porous bodies, foams, non-woven fabrics, etc. can be used.

[0049] Examples of the first positive electrode active material 132 include layered compounds such as lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), and compounds substituted with one or more transition metals; chemical formula Li 1+x Mn 2-x O 4 (where x is 0 to 0.33), LiMnO 3 , LiMn 2 O 3 , LiMnO 2 , etc. lithium manganese oxides; lithium copper oxide (Li 2 CuO 2 ); LiV 3 O 8 , V 2 O 5 , Cu 2 V 2 O 7 , etc. vanadium oxides; chemical formula LiNi 1-x M x O 2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3) Ni-site type lithium nickel oxides represented by; chemical formula LiMn 2-x M x O 2 (where M = Co, Ni, Fe, Cr, Zn or Ta and x = 0.01 to 0.1) or Li 2 Mn 3 MO 8A lithium manganese composite oxide represented by (where M = Fe, Co, Ni, Cu, or Zn); a part of Li in the chemical formula is substituted with an alkaline earth metal ion, LiMn 2 O 4 ; a disulfide compound; Fe 2 (MoO 4 ) 3 、LiNi x Mn 2-x O 4 (0.01 ≦ x ≦ 0.6), etc. can be used.

[0050] On the other hand, a conductive material and a binder can be mixed with the first positive electrode active material 132, and a filler may be further added if necessary.

[0051] The conductive material is usually added in an amount of 1% to 50% by weight based on the total weight of the mixture containing the first positive electrode active material 132. Such a conductive material is not particularly limited as long as it does not induce a chemical change in the battery and has conductivity. Examples of the conductive material include graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0052] The binder is a component that facilitates the binding of the first positive electrode active material 132 and the conductive material and the binding to the current collector, and is usually added in an amount of 1% to 50% by weight based on the total weight of the mixture containing the first positive electrode active material 132. Examples of such binders include 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, various copolymers, and the like.

[0053] The thickness of the first single cell 100 including each of the above-described components is 400 μm or less, preferably in the range of 150 μm to 250 μm, and more preferably in the range of 150 μm to 200 μm.

[0054] The second single cell 200 has a structure similar to that of the first single cell 100, and is laminated in the order of the second separator 210, the second negative electrode 220, the second separator 210, and the second positive electrode 230 from the bottom.

[0055] Here, the second separator 210 may be the same as the first separator 110 of the first single cell 100 described above. Also, since the second negative electrode 220 may have the same configuration as the first negative electrode 120 described above, duplicate explanations are omitted.

[0056] The second positive electrode 230 includes a second positive electrode current collector 231, a second positive electrode active material 232 applied to the lower surface of the second positive electrode current collector 231, and an insulating coating layer 233 located on the upper surface of the second positive electrode current collector 231.

[0057] The second positive electrode current collector 231 and the second positive electrode active material 232 may have the same configurations as the first positive electrode current collector 131 and the first positive electrode active material 132 described above, respectively.

[0058] The insulating coating layer 233 located on the upper surface of the second positive electrode current collector 231, that is, the upper part of the outermost contour of the electrode assembly, may be made of an insulating material.

[0059] The material of such an insulating coating layer 233 is preferably selected from one or more of polyethylene terephthalate (PET), polypropylene (PP), and ceramic, and more preferably polypropylene (PP) or ceramic.

[0060] In particular, the material of the insulating coating layer 233 is most preferably ceramic, because the mechanical strength of the second positive electrode 230 is improved by the formation of the ceramic coating layer, and furthermore, since it can maintain a somewhat rigid state, it is easy to transport and stack the second positive electrode 230.

[0061] Here, the thickness of the insulating coating layer 233 is preferably in the range of 10 μm to 20 μm.

[0062] When forming the surface exposed to the outside in a state of being located on the outermost contour of the electrode assembly with the insulating coating layer 233 in this way, the insulating state between the electrode assembly and the battery case can be maintained without a separate separator covering the entire electrode assembly.

[0063] Furthermore, while a half-cell composed of a separator, a negative electrode, and a separator is located at the uppermost end of the conventional electrode assembly, in the present invention, based on the second positive electrode current collector, the second positive electrode active material is applied to the lower surface, and a second positive electrode provided with an insulating coating layer on the upper surface is additionally provided on the upper surface of the separator. Therefore, compared with the conventional half-cell, the thickness of the half-cell increases, and thus there is an advantage that the stability of processes such as transfer and stacking of the half-cell can be expected.

[0064] On the other hand, the thickness of the second monocell 200 including each of the above-described configurations is 400 μm or less, preferably in the range of 150 μm to 250 μm, and more preferably in the range of 150 μm or more and less than 200 μm.

[0065] The manufacturing method of the electrode assembly according to the present invention having the above-described configuration includes a first step of preparing one or more first monocells 100 and second monocells 200, and a second step of sequentially laminating one or more first monocells 100 and second monocells 200 from below.

[0066] As described above, the first monocell 100 has a structure in which a first separator 110, a first negative electrode 120, a first separator 110, and a first positive electrode 130 are laminated in this order from below, and the second monocell 200 has a structure in which a second separator 210, a second negative electrode 220, a second separator 210, and a second positive electrode 230 are laminated in this order from below.

[0067] Since 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 monocell 100 and the second separator 210, the second negative electrode 220, the second separator 210, and the second positive electrode 230 constituting the second monocell 200 are as described above, duplicate explanations are omitted.

[0068] The present invention can be a pouch-type secondary battery in which the above-described electrode assembly is housed. Further, the present invention can be a battery module or a battery pack including the secondary battery described above.

[0069] Those having ordinary knowledge in the field to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above content.

Explanation of Reference Numerals

[0070] 100 First monocell 110 First separator 120 First negative electrode 121 First negative electrode current collector 122 First negative electrode active material 130 First positive electrode 131 First positive electrode current collector 132 First positive electrode active material 200 Second monocell 210 Second separator 220 Second negative electrode 221 Second negative electrode current collector 222 Second negative electrode active material 230 Second positive electrode 231 Second positive electrode current collector 232 Second positive electrode active material 233 Insulating coating layer

Claims

1. one or more first monocells; a second mono-cell stacked on top of the first mono-cell; The second monocell is provided with an insulating coating layer.

2. The electrode assembly of claim 1 , wherein the insulating coating layer is made of at least one of polyethylene terephthalate (PET), polypropylene (PP), and ceramic.

3. The electrode assembly of claim 2 , wherein the insulating coating layer is ceramic.

4. 3. The electrode assembly of claim 2, wherein the second monocell is formed by stacking a second separator, a second anode, a second separator, and a second cathode in this order from the bottom, and the insulating coating layer is provided on the second cathode.

5. The electrode assembly of claim 4 , wherein the second positive electrode is formed by stacking a second positive electrode active material, a second positive electrode current collector, and the insulating coating layer in this order from the bottom.

6. The electrode assembly of claim 3 , wherein the second monocell has a thickness in the range of 150 μm to 250 μm.

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

8. 5. The electrode assembly of claim 4, wherein the first monocell is formed by stacking a first separator, a first anode, a first separator, and a first cathode in this order from a bottom side, and at least one of the first anode and the second anode for storing lithium ions contains silicon.

9. The electrode assembly according to claim 8 , wherein the silicon is 95% by weight or more based on the negative electrode active material.

10. The electrode assembly of claim 8, wherein the thickness of the first monocell is in the range of 150 μm to 250 μm.

11. The electrode assembly of claim 10, wherein the thickness of the first monocell is in the range 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 first step of providing one or more first monocells and a second monocell; a second step of stacking one or more of the first mono-cells and one of the second mono-cells in sequence from the bottom; The first monocell is formed by stacking a first separator, a first negative electrode, a first separator, and a first positive electrode in this order from the bottom, The second monocell is formed by stacking a second separator, a second negative electrode, a second separator, and a second positive electrode in this order from the bottom, the second positive electrode comprises a second positive electrode current collector, a second positive electrode active material on a lower surface of the second positive electrode current collector, and an insulating coating layer 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 layer is a ceramic.

15. The method of claim 14 , wherein at least one of the first negative electrode and the second negative electrode comprises silicon.

Images