KR20230004051A - Electrode assembly having insulation coating portion, preparation method thereof, and secondary battery including the electrode assembly - Google Patents

Abstract

The present invention relates to an electrode assembly including an insulating coating unit, a manufacturing method thereof, and a secondary battery including the electrode assembly. The insulating properties and physical properties of the electrode assembly can be improved by forming an insulating coating unit in a spare region of a separator. The electrode assembly of the present invention includes a positive electrode, a negative electrode, and a separator positioned between the positive electrode and the negative electrode.

Description

Electrode assembly including an insulating coating, a method for manufacturing the same, and a secondary battery including the electrode assembly

The present invention relates to an electrode assembly including an insulating coating, a method for manufacturing the same, and a secondary battery including the electrode assembly.

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing, and accordingly, research on secondary batteries that can meet various needs is being conducted.

Typically, in terms of battery shape, demand for prismatic secondary batteries and pouch-type secondary batteries, which can be applied to products such as mobile phones with a thin thickness, is high, and in terms of materials, advantages such as high energy density, discharge voltage, and output safety are high. There is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries.

These secondary batteries can be classified into cylindrical battery cells, prismatic battery cells, pouch-type battery cells, and the like, depending on their shapes. Among them, a pouch type battery cell that can be stacked with a high degree of integration, has a high energy density per weight, and is inexpensive and easily deformable has attracted much attention.

On the other hand, the electrode assembly built into the pouch-type battery case is a power generating device capable of charging and discharging with a laminated structure of anode/separator/cathode. It is classified into a roll type and a stack type in which a plurality of positive and negative electrodes of a predetermined size are sequentially stacked in a state in which a separator is interposed.

1 is a schematic diagram showing a stacked battery cell, and FIG. 2 is a schematic diagram showing how a stacked battery cell is changed when the battery cell is damaged. Referring to FIGS. 1 and 2 , a stack type battery cell has a structure in which a plurality of positive electrodes and negative electrodes are sequentially stacked in a state in which a separator is interposed. However, electrode plates such as positive and negative electrodes of a battery cell may be deformed upon external impact, and such electrode plate deformation is a primary cause of ignition or explosion of the battery cell. Accordingly, stiffness against external impact is recognized as a major factor in determining the quality of a battery cell.

3 is a diagram schematically showing a collision test process of a battery cell, and FIG. 4 is a diagram illustrating a photograph of the appearance of a battery cell after a collision test of the battery cell. Referring to FIG. 3 , a crash test on a battery cell is performed by dropping an object having a predetermined weight from a specific height in a state in which the battery cell is fixed to impact the battery cell. Specifically, the crash test of the battery cell is a test on the front (wide sides) and the side (narrow sides) of the battery cell, and an object weighing 9.1 kg is dropped on the battery cell from a height of about 61 cm to apply an impact, and ignition or not Check whether it is safe or not.

Referring to FIG. 4 , when performing a test in which an impact is applied to the front (wide sides) of a conventional pouch-type battery cell, it can be seen that the side portion of the battery cell has a greater deformation than the inside. This means that the stability of the side part of the battery cell is weaker than that of the inner part.

In particular, the side portion of the battery cell may tear the separator due to external impact, and in this case, there is a risk of short circuit due to contact between the positive electrode and the negative electrode. In addition, even when a large current flows within a short time due to overcharging, external short circuit, nail penetration, local crush, etc., the battery is heated due to heat generation and there is a risk of ignition/explosion.

Meanwhile, various methods such as attaching an insulating tape in a predetermined size on an electrode tab or forming an insulating coating layer have been conventionally attempted to reduce the possibility of short circuit of an electrode under an external shock or high temperature of a battery cell.

However, since there is no technology for preventing deformation of the side region of the battery cell, there is a need to develop technology for an electrode assembly capable of preventing deformation of the side region of the battery cell and improving safety.

Republic of Korea Patent No. 10-1768195

The present invention is to solve the above problems, and an object of the present invention is to provide a secondary battery including an electrode assembly including an insulating coating, a manufacturing method thereof, and the electrode assembly.

The present invention relates to an electrode assembly including an insulating coating portion. In one example, the present invention relates to an electrode assembly including a positive electrode, a negative electrode, and a separator positioned between the positive electrode and the negative electrode, wherein the electrode assembly includes n separators having a larger size than the positive electrode and the negative electrode, (n is an integer of 2 or more), a structure in which one electrode of the anode and cathode is interposed between the k-th separator and the k+1-th separator (k is an integer of 1 or more and n-1 or less), and the k-th separator An insulating coating portion may be formed in a spare area between the and k+1 th separator to contact at least one end of the electrode.

In another example, the insulating coating part may have a structure in which a separator and a partial region of one surface of the electrode overlap each other.

In addition, the width W1 of each of the insulating coating parts may be formed in an area of 15% or less based on the width W2 of the separator.

In another example, when the insulating coating portion is coated so as to overlap the separator and the electrode, the ratio (W1:W3) of the width length (W1) of each insulating coating portion and the width length (W3) of the overlapped region of the electrode is 5 :5 to 8:2.

In addition, in the electrode assembly according to the present invention, the k-th separator and the k+1-th separator may have a structure in which they are adhered to each other by an insulating coating part.

In one example, the insulating coating part may be a mixture of a binder polymer and inorganic particles.

In specific examples, the binder polymer is polyvinylidene fluoride, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic rubber, butyl rubber, Fluorine rubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polyethylene oxide, polyvinylpyrrolidone, polyepicrohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylene A group consisting of propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, hydroxypropylmethylcellulose, hydroxypropylcellulose and diacetylcellulose It may be one or more selected from.

In addition, the inorganic particles may include alumina (Al ₂ O ₃ ), boehmite (AlOOH), silica (SiO ₂ ), titanium dioxide (TiO ₂ ), aluminum hydroxide (Al(OH) ₃ ), magnesium oxide (MgO), Magnesium hydroxide (Mg(OH) ₂ , zinc oxide (ZnO), barium titanate (BaTiO), aluminum nitride (AIN), boron nitride (BN), silicon carbide (SiC), beryllium oxide (BeO), potassium nitrate ( KNO ₃ ) and monobasic ammonium phosphate (NH ₄ H ₂ PO ₄ ) may be at least one selected from the group consisting of.

Furthermore, the separator is made of polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, Any one polymer selected from the group consisting of polyethersulfone, polyphenyleneoxide, cyclic olefin copolymer, polyphenylenesulfide and polyethylenenaphthalene, or these It may be a polymer film formed of a mixture of two or more of them, or a multilayer thereof, a woven fabric, or a non-woven fabric.

Meanwhile, the insulating coating part may be formed along two sides adjacent to the side where the electrode tab of the electrode is formed.

The present invention provides a method for manufacturing the electrode assembly described above. In the manufacturing method of an electrode assembly including a cathode, an anode, and a separator positioned between the cathode and the anode, n separators having a larger size than the cathode and anode (n is an integer of 2 or more), the k th separator and k + 1 and preparing a laminate by stacking one electrode of a cathode and an anode between the th separator (k is an integer of 1 or more and n−1 or less). On the other hand, in the step of preparing the laminate, after laminating an electrode on one side of the separator, the step of applying an insulating coating liquid to the spare area of the separator, wherein the insulating coating liquid is applied so as to come into contact with at least one end of the electrode. process may be included.

In addition, the manufacturing method of the electrode assembly according to the present invention comprises the steps of drying the laminate to which the insulating coating liquid is applied at a temperature range of 50 ° C to 200 ° C; and pressing the laminate in the above temperature range.

The process of applying the insulating coating liquid to the spare area of the separator may include applying the insulating coating liquid so that a partial area of the separator and one surface of the electrode overlap.

In addition, in the process of applying the insulating coating liquid to the spare area of the separator, the insulating coating liquid may be applied by at least one method selected from the group consisting of spray coating, slot die coating, and roll coating. there is.

The present invention provides a secondary battery including the electrode assembly described above. In a specific example, the secondary battery according to the present invention may have a structure in which the electrode assembly is embedded in a pouch.

In a specific example, the electrode assembly may include at least one selected from the group consisting of a mono-cell and a bi-cell.

According to the electrode assembly including the insulating coating part of the present invention, the manufacturing method thereof, and the secondary battery including the electrode assembly, the insulating properties and physical properties of the electrode assembly can be improved by forming the insulating coating part in the spare area of the separator. there is.

In addition, damage to the inside of the electrode assembly can be prevented by the insulating coating portion, thereby suppressing the occurrence of a short circuit, and there is an effect of preventing the risk of explosion and fire due to the short circuit.

1 is a schematic diagram showing a typical stacked type battery cell.
2 is a schematic diagram showing how a stacked battery cell is changed when the battery cell is damaged.
3 is a diagram schematically showing a collision test process of a battery cell.
4 is a diagram illustrating a photograph of the appearance of a battery cell after a collision test of the battery cell.
5 is a schematic diagram of an electrode assembly according to the present invention.
6 is a front view of an electrode assembly according to the present invention
7 is a schematic view showing a separator having an insulating coating in one embodiment of the present invention.
8 is a front view of an electrode assembly according to the present invention.
9 is a schematic diagram showing a separator having an insulating coating in another embodiment of the present invention.
10 is a flowchart illustrating a method of manufacturing an electrode assembly according to the present invention.
11 and 12 are diagrams schematically illustrating a manufacturing method of an electrode assembly according to the present invention.

Since the present invention can have various changes and various embodiments, specific embodiments will be described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In the present invention, the term "comprises" or "has" is intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Further, in the present invention, when a part such as a layer, film, region, plate, etc. is described as being “on” another part, this includes not only the case where it is “directly on” the other part, but also the case where another part is present in the middle thereof. . Conversely, when a part such as a layer, film, region, plate, or the like is described as being “under” another part, this includes not only being “directly under” the other part, but also the case where there is another part in the middle. In addition, in the present application, being disposed "on" may include the case of being disposed not only on the upper part but also on the lower part.

In the present invention, "electrode assembly" refers to only one or more unit cells, or refers to an assembled form formed of two or more unit cells with a separator interposed therebetween. In the present invention, a "unit cell" is a unit in which a positive electrode, a negative electrode, and a separator are interposed between the positive electrode and the negative electrode, and it is understood that, for example, one or more types of unit cells may be included.

In addition, the electrode assembly in the present invention provides a stacked electrode assembly. The "stacked electrode assembly" may refer to an electrode assembly in which a plurality of positive and negative electrodes cut in units of a predetermined size are sequentially stacked with a separator interposed therebetween.

Hereinafter, an electrode assembly including an insulating coating according to the present invention, a manufacturing method thereof, and a secondary battery including the electrode assembly according to the present invention will be described in detail with reference to the drawings.

[First Embodiment]

The present invention provides an electrode assembly including an insulating coating portion in a first embodiment.

electrode assembly

5 is a schematic diagram of an electrode assembly according to the present invention, and FIG. 6 is a cross-sectional view (A-A') of the electrode assembly according to the present invention. 5 to 6, the electrode assembly 100 according to the present invention includes a positive electrode 1111, a negative electrode 1112, and a separator 120 positioned between the positive electrode 1111 and the negative electrode 1112. do.

The electrode assembly 100 may include n (n is an integer of 2 or more) separators 120 having a larger size than the positive electrode 1111 and the negative electrode 1112 . In addition, one electrode 110 of the anode 1111 and the cathode 1112 is interposed between the k-th separator and the k+1-th separator (k is an integer of 1 or more and n-1 or less).

Meanwhile, in the electrode assembly 100 according to the present invention, the spare area between the k-th separator 120 and the k+1-th separator 120 has an insulating coating along the length so as to contact at least one end of the electrode 110. (130) is characterized in that it is formed. In a specific example, the insulating coating portion 130 may have a structure formed along two sides of the electrode 110 adjacent to the side where the electrode tab 111 is formed. Typically, the positive electrode 1111 and the negative electrode 1112 include a current collector and a mixture layer formed on one or both surfaces of the current collector, and an electrode tab 111 extending from the current collector is formed. The coating unit 130 may be formed along the longitudinal direction of the separator 120 and may have a structure formed along two sides adjacent to the side where the electrode tab 111 is formed. The insulating coating part 130 may be formed in the spare area of the separator 120 to improve the safety of the electrode assembly 100 . Here, the term "spare area" means an empty space at both ends of the electrode 110 when the electrode 110 is disposed between the k-th separator 120 and the k+1-th separator 120. can Specifically, it means both sides along the length direction of the pouch-type secondary battery between the k-th separator 120 and the k+1-th separator 120, and the electrode tab 114 of the electrode 110 in the separator 120 It may mean two sides orthogonal to the formed side.

Conventionally, a method of forming an insulating tape or an insulating coating layer on the electrode tab 111 has been attempted to reduce the possibility of a short circuit of the electrode 110 under external impact or high temperature of the battery cell. However, there is a problem in that the electrode 110 is short-circuited due to deformation of the side region or tearing of the separator due to external impact of the battery cell. In particular, in the pouch-type battery cell, the length of the electrode 110 is made long in order to increase the energy density. In this case, the side region may be structurally less stable than the electrode tab 111 region. Accordingly, the present invention provides an insulating coating portion in contact with both ends of the electrode 110 in the spare area between the k-th separator 120 and the k + 1-th separator 120 in order to improve the structural stability of the battery cell or electrode assembly ( 130) provides an electrode assembly 100 having a structure formed thereon.

In the electrode assembly 100 according to the present invention, the k-th separator 120 and the k+1-th separator 120 may have a structure in which they are adhered to each other by the insulating coating part 130. In particular, the electrode assembly 100 including the insulating coating part 130 is coated on the separator 120, and damage to the separator 120 can be prevented. In addition, even if damage occurs to the separator 120, a hard short that occurs momentarily can be prevented by including the insulating coating part 130 in the spare area so that a large current flows.

In addition, the separator 120 is interposed between the anode 1111 and the cathode 1112, and an insulating thin film having high ion permeability and mechanical strength may be used. Separator 120 is not particularly limited as long as it is commonly used in the art, but specifically, chemical resistant and hydrophobic polypropylene; glass fiber; Alternatively, a sheet or non-woven fabric made of polyethylene may be used. In some cases, a composite separator 120 in which inorganic particles/organic particles are coated with an organic binder polymer on a porous polymer substrate such as the sheet or non-woven fabric may be used. there is. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may serve as a separator. In addition, the separator may have an average pore diameter of 0.01 to 10 μm and an average thickness of 5 to 300 μm.

In one example, the separator 120 is made of polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzene selected from the group consisting of polybenzimidazole, polyethersulfone, polyphenyleneoxide, cyclic olefin copolymer, polyphenylenesulfide and polyethylenenaphthalene It may be a polymer film formed of any one polymer or a mixture of two or more of them, or a multi-layer, woven or non-woven fabric thereof. In a specific example, the separator 120 is a polymer film selected from the group consisting of polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, and polyester. In some cases, a composite separator coated with an organic binder polymer such as polyvinylidene fluoride (PVdF) or styrene butadiene rubber (SBR) may be used. For example, when a composite separator coated with an organic binder polymer such as polyvinylidene fluoride (PVdF) or styrene-butadiene rubber (SBR) is used for the separator 120, the insulating coating portion 130 and It is more easily bonded and the safety of the electrode assembly 100 can be improved.

The insulating coating portion 130 may have a structure coated with an insulating material that is a mixture of a binder polymer and inorganic particles. In a specific example, the insulating coating part 130 may provide the insulating coating part 130 having excellent tensile strength and impact strength by using an insulating material in which inorganic particles are mixed with a binder polymer.

In specific examples, the binder polymer is polyvinylidene fluoride, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic rubber, butyl rubber, fluorine Rubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polyethylene oxide, polyvinylpyrrolidone, polyepicrohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylene propylene from the group consisting of diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, hydroxypropylmethylcellulose, hydroxypropylcellulose and diacetylcellulose It may be one or more selected species. or polyvinylidene fluoride, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic rubber, butyl rubber, fluororubber and polytetrafluoroethylene It may be one or more. For example, the binder polymer may be polyvinylidene fluoride.

In addition, the inorganic particles include alumina (Al ₂ O ₃ ), boehmite (AlOOH), silica (SiO ₂ ), titanium dioxide (TiO ₂ ), aluminum hydroxide (Al(OH) ₃ ), magnesium oxide (MgO), hydroxide Magnesium (Mg(OH) ₂ , Zinc Oxide (ZnO), Barium Titanate (BaTiO), Aluminum Nitride (AIN), Boron Nitride (BN), Silicon Carbide (SiC), Beryllium Oxide (BeO), Potassium Nitrate (KNO) ₃ ) and monobasic ammonium phosphate (NH ₄ H ₂ PO ₄ ), and may be at least one selected from the group consisting of, specifically, alumina (Al ₂ O ₃ ), boehmite (AlOOH), and silica (SiO ₂ ). It may be one or more selected from the group consisting of.

Furthermore, the inorganic particles may be at least one selected from the group consisting of potassium nitrate (KNO ₃ ) and monobasic ammonium phosphate (NH ₄ H ₂ PO ₄ ). For example, when potassium nitrate (KNO ₃ ) and monobasic ammonium phosphate (NH ₄ H ₂ PO ₄ ) are used as inorganic particles, there is an effect of delaying thermal conversion when a battery cell ignites or explodes.

The inorganic particles may have an average particle diameter ranging from 0.001 μm to 100 μm, 0.01 μm to 70 μm, or 1 μm to 50 μm. If the particle diameter of the inorganic particles is less than the lower limit in the above range, the stress between the inorganic particles may increase and the particles may be agglomerated, and it may be difficult to uniformly disperse in the polymer binder. , sedimentation of inorganic particles may occur, and it may be difficult to form a uniform insulating coating portion 113 .

The weight ratio of the binder polymer to the inorganic particles may range from 1:99 to 50:50, or from 5:95 to 30:70. On the other hand, if the content ratio of the binder polymer is too high, the pore size and porosity of the separator may be reduced, and if the content of inorganic particles is too large, the adhesive strength with the separator 120 is reduced because the content of the binder polymer is too small. may be weakened.

The mixture of the polymeric binder and the inorganic particles is one or two or more solvents selected from water, glycerol, ethylene glycol, propylene glycol, dimethyl sulfoxide, dimethyl formamide, acetonitrile, ethylene carbonate, furfuryl alcohol, and methanol, if necessary. can include At this time, the solid content with respect to 100 parts by weight of the solvent may be 1 to 50 parts by weight, or 5 to 40 parts by weight, or 10 to 40 parts by weight.

7 is a schematic view showing a separator having an insulating coating in one embodiment of the present invention. Referring to FIG. 7, the separator 120 having a larger size than the electrode 110 has a structure in which the electrode 110 is stacked on one surface and the insulating coating 130 is formed along both sides of the electrode 110. . That is, as described above, the insulating coating portion 130 may be formed in the spare area along the length of the separator 130 .

At this time, the insulating coating portion 130 may be in contact with both ends of the electrode 110 . Here, both ends of the electrode 110 mean ends of two sides adjacent to the side where the electrode tab 111 is formed. The insulating coating portion 130 is formed to come into contact with both ends of the electrode 110 to prevent the active material from escaping from both ends of the mixture layer, and to provide thermal stability even if the active material is detached. there is.

The width W1 of each insulating coating portion 130 may be 15% or less of the width W2 of the separator 120 . Specifically, the width W1 of each insulating coating portion 130 is 2% to 15% based on the width W2 of the separator 120; 4% to 14%; 6%~13%; 8%~12%; 10%~11%; or in the range of 10%. If the width W1 of each insulating coating portion 130 is less than the lower limit of the range based on the width W2 of the separator 120, the width of the insulating coating portion 113 formed on the electrode 110 Since the length W1 is too small, it may be difficult to prevent deformation of the side region of the battery cell, and the width W1 of each insulating coating portion 113 is within the above range based on the width W2 of the separator 120. When the upper limit is exceeded, it is difficult to control the change in shape of the battery cell, which may cause appearance defects. The width W1 of the insulating coating portion 113 is not particularly limited, and the insulating material may range from 0.5 mm to 10 mm, for example.

Furthermore, although not shown in the drawing, the electrode 110 may further include an insulating coating portion (not shown) along the side where the electrode tab 111 is formed.

The electrode assembly 100 including the insulating coating part 130 according to the present invention can prevent the occurrence of a short circuit by preventing damage to the inside of the electrode assembly 100 by the above-described configuration, and the short circuit can prevent the risk of explosion and fire caused by

[Second Embodiment]

The present invention provides an electrode assembly including the above-described insulating coating portion in a second embodiment.

electrode assembly

8 is a front view of an electrode assembly according to the present invention, and FIG. 9 is a schematic diagram showing a separator formed with an insulating coating in another embodiment of the present invention. 8 to 9, the electrode assembly 200 according to the present invention includes n separators (n is an integer greater than or equal to 2) having a larger size than the positive electrode 2111 and the negative electrode 2112, and the k-th separator The electrode 110 is interposed between the separator 220 and the k+1 th separator 220, and both ends of the electrode 110 are in the spare area between the k th separator 220 and the k+1 th separator 220. It is a structure in which the insulating coating portion 230 in contact with is formed.

In this case, the insulating coating portion 230 may be formed along the length of the electrode 210 and may have a structure formed to contact at least one end portion along the length of the electrode 210 . In a specific example, the insulating coating portion 230 may be formed along two sides of the electrode 210 adjacent to the side on which the electrode tab 211 is formed, and a partial area of the separator 220 and one surface of the electrode 210. It can be coated so that it overlaps. This means that the insulating coating part 230 is formed on the interface between the separator 220 and the electrode 210, and the insulating coating part 230 may cover both ends of the electrode 210. .

In this case, internal damage to the electrode assembly 200 may be prevented to suppress occurrence of a short circuit, and separation of the active material or the like from both ends of the mixture layer in the electrode 210 may be prevented.

A ratio (W1:W3) of the width W1 of each insulating coating portion 230 and the width W3 of the overlapped region of the electrode 210 may be in the range of 5:5 to 8:2. More specifically, the ratio (w1:w3) of the width W1 of each insulating coating portion 230 and the width W3 of the region overlapping the electrode 210 may be 6:4 to 7:3, , for example 7:3. On the other hand, when the width W1 of the overlapped region of each insulating coating portion 230 is too long, the area of the insulating coating portion 230 increases and the area of the mixture layer decreases, so that the energy density of the battery cell increases. may decrease, and the performance of the battery cell may also deteriorate.

Meanwhile, although the region where the electrode 210 overlaps with the insulating coating 230 is not shown in the figure, one surface of the holding part of the electrode 210, one surface of the uncoated part of the electrode 210, or the holding part and the uncoated part of the electrode 210 It can be coated on one side.

The electrode assembly 200 including the insulating coating portion 230 according to the present invention can prevent the occurrence of a short circuit by preventing damage to the inside of the electrode assembly 200 by the above-described configuration, and the short circuit can prevent the risk of explosion and fire caused by

[Third Embodiment]

The present invention provides a method for manufacturing an electrode assembly including an insulating coating portion described above in a third embodiment.

Manufacturing method of electrode assembly

10 is a flow chart showing a manufacturing method of an electrode assembly according to the present invention, and FIGS. 11 and 12 are diagrams schematically showing a manufacturing method of an electrode assembly according to the present invention. 10 to 12, the method of manufacturing an electrode assembly according to the present invention includes an anode 3111, a cathode 3112, and a separator 320 positioned between the anode 3111 and the cathode 3112. Manufacturing the assembly 300 includes preparing a laminate coated with an insulating coating solution, drying the insulating coating solution of the laminate, and pressing the laminate.

Preparing a laminate (S10)

In the manufacturing method of the electrode assembly according to the present invention, n separators 320 (n is an integer of 2 or more) having a larger size than the positive electrode and the negative electrode, the k th separator 320 and the k + 1 th separator 320 k An integer of 1 or more and n−1 or less), and preparing a laminate by stacking one electrode 310 of an anode and a cathode between them.

At this time, in the step of preparing the laminate, the step of laminating the electrode 310 on one side of the separator and then applying the insulating coating liquid to the spare area of the separator 320, including the step of applying the insulating coating liquid to the electrode 310 It may include a process of applying along two sides adjacent to the side on which the electrode tab 311 of the electrode 310 is formed so as to come into contact with both end portions of the electrode 310 .

In the step of preparing the laminate, an insulating coating liquid may be applied to a spare area of the separator 320 after interposing the electrode 310 in the separator 320 . In addition, in an undried state of the insulating coating liquid, it is possible to prepare a laminate coated with the insulating coating liquid by repeating the above process. That is, the step of preparing the laminate may mean a step of preparing a laminate coated with an insulating coating liquid. For example, after the negative electrode 3112 is interposed between the first separator 320 , an insulating coating liquid may be applied so as to be in contact with both ends of the negative electrode 3112 . In addition, a second separator 320 may be stacked on one surface of the negative electrode 3112 in an undried state of the insulating coating liquid. Then, after the anode 3111 is interposed on one surface of the second separator 320, an insulating liquid may be applied so as to be in contact with both ends of the anode 3111. A laminate may be prepared by assembling one or more of these unit cells. Here, a process of stacking bi-cells having a first separator/cathode/second separator/cathode structure as a unit cell has been described, but is not limited thereto.

Meanwhile, the process of applying the insulating coating liquid to the spare area of the separator 320 is one or more methods selected from the group consisting of spray coating, slot die coating, and roll coating. can be spread with For example, the process of applying the insulating coating liquid may be performed by slot die coating or roll coating. At this time, the insulating coating liquid may be coated so as to come into contact with both ends of the electrode 310 . Since the type of the insulating coating liquid has been described above, a detailed description thereof will be omitted.

In another example, in the process of applying the insulating coating liquid to the spare area of the separator, the insulating coating liquid may be applied such that a partial area of one surface of the separator 120 and the electrode 310 overlaps. In this case, internal damage to the electrode assembly 300 may be prevented to suppress occurrence of a short circuit, and separation of an active material or the like from both ends of the mixture layer in the electrode may be prevented.

Drying the insulating coating solution of the laminate (S20)

The manufacturing method of the electrode assembly according to the present invention includes drying the insulating coating solution of the laminate (see FIG. 12). In the step of drying the insulating coating liquid, moisture may be removed by completely drying the insulating coating liquid by a drying method commonly known in the art. In a specific example, drying may be applied by changing a hot air method, a direct heating method, an induction heating method, etc. at a temperature at which all moisture volatilizes, but is not limited thereto. For example, drying the insulating coating liquid of the laminate may be performed by a hot air method.

At this time, the drying temperature may be in the range of 50 °C to 200 °C, and may be 60 to 150 °C or 70 to 100 °C. On the other hand, when the drying temperature of the insulating coating liquid is less than 50 ° C, it may be difficult to completely dry the insulating coating liquid because the temperature is too low, and when it exceeds 200 ° C, the drying temperature is too high and deformation of the electrode or separator may occur.

Pressing the laminate (S30)

The manufacturing method of the electrode assembly according to the present invention includes the step of pressurizing the laminate. In a specific example, it is for bonding between each component of the electrode assembly 300, and may be performed through a conventional press. Meanwhile, the pressing of the laminate may be performed at the same temperature as the drying temperature. When pressure is applied while temperature is applied to the laminate, the radical units within the electrode assembly 300 may adhere to each other. In a specific example, the k-th separator 320 and the k+1-th separator 320 may be adhered to each other by the insulating coating part 330 .

Accordingly, in the spare area between the k-th separator 320 and the k+1-th separator 320, the electrode assembly 300 including the insulating coating portion 330 in contact with both ends of the electrode 310 is easily manufactured. can do.

[Fourth Embodiment]

The present invention provides a secondary battery including the electrode assembly described above.

secondary battery

The electrode assembly described above may be built into a pouch and manufactured as a secondary battery, and a plurality of the secondary batteries may be electrically connected to each other to be manufactured as a secondary battery module. Meanwhile, in the present invention, the secondary battery may be a lithium secondary battery.

The electrode assembly according to the present invention can be stacked, the electrode tabs extending from each electrode plate of the electrode assembly, and the electrode lead is connected to a plurality of electrode tabs extending from each electrode plate, for example, by welding. Each is electrically connected and exposed to the outside of the pouch. In addition, at least one electrode of the positive and negative electrodes may include an insulating coating part along two sides adjacent to the side on which the electrode tab is formed. The pouch is usually made of an aluminum laminate sheet and may provide a space for accommodating an electrode assembly. Meanwhile, the electrode leads may be drawn out of the pouch and may extend in the same direction or opposite directions.

In the present invention, the electrode may be stacked together with a conventional electrode having an electrode active material layer formed on both sides of a current collector to form a unit cell such as a bi-cell or a mono-cell. In a specific example, the electrode assembly in the secondary battery according to the present invention may include at least one selected from the group consisting of a mono-cell and a bi-cell. More specifically, in the mono cell, electrodes having opposite polarities are disposed on both sides of the unit cell. In addition, the bi-cell is a unit cell that has the same polarity on both sides of the cell, such as a unit structure of an anode/separator/cathode/separator/anode and a unit structure of cathode/separator/anode/separator/cathode. These monocells and bicells are not particularly limited in the number of separators of the positive and negative electrodes constituting them as long as the electrodes on both sides of the unit cell have the same structure. However, when two or more unit cells are stacked, a plurality of unit cells must be stacked so that the positive electrode and the negative electrode face each other with a separator interposed between each unit cell. For example, in order to construct an electrochemical cell including a secondary battery using a bi-cell, a bi-cell (anode bi-cell) and a cathode/separator/ A plurality of bi-cells must be stacked so that the bi-cells (cathode bi-cells) of the anode/separator/cathode structure face each other. In some cases, a larger number of bi-cells are also possible, for example, anode/separator/cathode/separator/anode/separator/cathode/separator/anode and cathode/separator/anode/separator/cathode/ A bi-cell having a separator/anode/separator/cathode structure is also possible.

On the other hand, the electrode assembly is characterized by including the electrode assembly according to the first or second embodiment of the present invention described above, and due to this feature, the advantage of improving the insulation characteristics and physical properties of the electrode assembly there is.

In addition, damage to the inside of the electrode assembly can be prevented by the insulating coating portion, thereby suppressing the occurrence of a short circuit, and there is an effect of preventing the risk of explosion and fire due to the short circuit.

In the above, the present invention has been described in more detail through drawings and examples. However, since the configurations described in the drawings or embodiments described in this specification are only one embodiment of the present invention and do not represent all of the technical spirit of the present invention, various equivalents and It should be understood that variations may exist.

10, 100, 200, 300: electrode assembly
110, 210, 310: electrode
111, 211, 311: electrode tab
11, 1111, 2111, 3111: anode
11', 1112, 2112, 3112: cathode
12, 120, 220, 320: separator
130, 230, 330: insulation coating part

Claims (16)

In the electrode assembly including a positive electrode, a negative electrode and a separator positioned between the positive electrode and the negative electrode,
The electrode assembly includes n separators having a size larger than that of the positive electrode and the negative electrode (n is an integer of 2 or more), and the k th separator and the k+1 th separator (k is an integer of 1 or more and n-1 or less). A structure in which one electrode of the anode and cathode is interposed between,
The electrode assembly having a structure in which an insulating coating is formed in contact with at least one end of the electrode in the spare area between the k th separator and the k + 1 th separator.
According to claim 1,
The electrode assembly having a structure in which the insulating coating part is coated so that the separator and a partial region of one surface of the electrode overlap.
According to claim 2,
The electrode assembly in which the width (W1) of the insulating coating portion is 15% or less based on the width (W2) of the separator.
According to claim 2,
The ratio (W1: W3) of the width length (W1) of the insulating coating part and the width length (W3) of the overlapping region of the electrode is in the range of 5:5 to 8:2.
According to claim 1,
The electrode assembly having a structure in which the k th separator and the k + 1 th separator are adhered to each other by the insulating coating portion.
According to claim 1,
The electrode assembly, characterized in that the insulating coating portion is a mixture of a binder polymer and inorganic particles.
According to claim 6,
The binder polymer is polyvinylidene fluoride, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic rubber, butyl rubber, fluororubber, poly Tetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polyethylene oxide, polyvinylpyrrolidone, polyepicrohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylenepropylene diene copolymer 1 selected from the group consisting of polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, hydroxypropylmethylcellulose, hydroxypropylcellulose and diacetylcellulose Electrode assemblies that are more than one species.
According to claim 6,
The inorganic particles include alumina (Al ₂ O ₃ ), boehmite (AlOOH), silica (SiO ₂ ), titanium dioxide (TiO ₂ ), aluminum hydroxide (Al(OH) ₃ ), magnesium oxide (MgO), and magnesium hydroxide. (Mg(OH) ₂ , zinc oxide (ZnO), barium titanate (BaTiO), aluminum nitride (AIN), boron nitride (BN), silicon carbide (SiC), beryllium oxide (BeO), potassium nitrate (KNO ₃ ) And at least one electrode assembly selected from the group consisting of monobasic ammonium phosphate (NH ₄ H ₂ PO ₄ ).
According to claim 1,
The separator is made of polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, poly Polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, poly Any one polymer selected from the group consisting of ethersulfone, polyphenyleneoxide, cyclic olefin copolymer, polyphenylenesulfide and polyethylenenaphthalene, or any of these An electrode assembly, characterized in that it is a polymer film formed of a mixture of two or more or a multilayer, woven or non-woven fabric thereof.
According to claim 1,
The electrode assembly wherein the insulating coating portion is formed along two sides adjacent to the side on which the electrode tab of the electrode is formed.
In the manufacturing method of an electrode assembly comprising a positive electrode, a negative electrode and a separator positioned between the positive electrode and the negative electrode,
Between the n separators (n is an integer of 2 or more) having a larger size than the anode and the cathode, and the k th separator and the k+1 th separator (k is an integer of 1 or more and n-1 or less), among the anode and cathode Preparing a laminate by stacking one electrode; Including,
In the step of preparing the laminate, after laminating an electrode on one surface of the separator, applying an insulating coating liquid to a spare area of the separator, so that the insulating coating liquid comes into contact with at least one end of the electrode. A method of manufacturing an electrode assembly comprising a coating process.
According to claim 11,
drying the insulating coating liquid applied to the laminate at a temperature range of 50° C. to 200° C.; and
The manufacturing method of the electrode assembly further comprising the step of pressurizing the laminate in the temperature range.
According to claim 11,
The process of applying the insulating coating liquid to the spare area of the separator includes applying the insulating coating liquid so that a partial area of the separator and one surface of the electrode overlaps.
According to claim 11,
In the process of applying the insulating coating liquid to the spare area of the separator, the insulating coating liquid is applied by at least one method selected from the group consisting of spray coating, slot die coating, and roll coating. Method for manufacturing an electrode assembly, characterized in that.
A secondary battery in which the electrode assembly according to claim 1 is embedded in a pouch.
According to claim 15,
The electrode assembly is a secondary battery comprising at least one selected from the group consisting of a mono-cell and a bi-cell.

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