KR102403673B1 - Electrode assembly, secondary battery and manufacturing method of electrode assembly - Google Patents

Abstract

An electrode assembly according to an embodiment of the present invention includes an electrode plate made of an electrode connected to an electrode tab, wherein the electrode tab is an uncoated region positioned at an edge region of the electrode plate, and the uncoated region is integrally formed with the electrode. do.

Description

Electrode assembly, secondary battery including the same, and method of manufacturing an electrode assembly

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

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. Accordingly, a lot of research has been done on secondary batteries that can meet various needs.

Secondary batteries are attracting a lot of attention as an energy source for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles, as well as mobile devices such as cell phones, digital cameras, and laptops.

A small battery pack in which one battery cell is packed is used for small devices such as mobile phones and cameras, but a battery pack in which two or more battery cells are connected in parallel and/or in series is used in mid- to large-sized devices such as notebook computers and electric vehicles. Packed medium or large battery packs are being used.

In terms of shape, the secondary battery may be classified into a cylindrical battery and a prismatic battery in which the electrode assembly is embedded in a cylindrical or prismatic metal can, and a pouch-type battery in which the electrode assembly is embedded in a pouch-type case of an aluminum laminate sheet.

The electrode assembly embedded in the battery case is a power generation device capable of charging and discharging having a stacked structure of positive electrode/separator/negative electrode, and a jelly-roll type, which is wound with a separator between the positive electrode and the negative electrode of a long sheet type coated with an active material, and a predetermined It may be classified as a stack type in which a plurality of positive and negative electrodes of a size are sequentially stacked with a separator interposed therebetween. In addition, a stack/folding type electrode assembly that is a mixture of a jelly-roll type and a stack type is also used.

An electrode tab is formed on the electrode plate of the electrode assembly to be connected to the electrode lead. Due to the notching of the electrode tab, the width of the electrode tab is shorter than the entire width of the electrode plate, and the thickness of the electrode tab is thin because the active material is not coated. can be folded In this case, errors may occur in reference points during cutting, matching, and lamination in the process of forming the electrode assembly. In addition, the rigidity of the electrode tab part is weak, and there is a limit to capacity improvement when using a compact structure.

Embodiments may provide an electrode assembly capable of preventing the electrode tab from being folded and increasing capacity in a battery cell of the same size, a secondary battery including the same, and a method of manufacturing the electrode assembly.

However, the problems to be solved by the embodiments of the present invention are not limited to the above problems and may be variously expanded within the scope of the technical idea included in the present invention.

An electrode assembly according to an embodiment of the present invention includes an electrode plate made of an electrode connected to an electrode tab, wherein the electrode tab is an uncoated region positioned at an edge region of the electrode plate, and the uncoated region is integrally formed with the electrode. do.

The electrode may include two protrusions spaced apart from the electrode tab, and a line connecting ends of the two protrusions may coincide with one side of the electrode tab.

A depression may be formed on one side of the electrode adjacent to the electrode tab and on the other side facing the electrode tab.

The electrode may have an “H” shape.

The electrode plate is formed in plurality, the electrode plate formed in plurality includes a positive electrode and a negative electrode, a separator is positioned between the positive electrode and the negative electrode, and the positive electrode and the negative electrode each include a positive electrode tab and a negative electrode tab, and the positive electrode , in the laminate including the separator and the negative electrode, the positive electrode tab and the negative electrode tab may be positioned opposite to each other with respect to the center of the laminate.

A depression portion is formed on one side of the positive electrode and one side of the negative electrode, respectively, the depression portion formed on the positive electrode and the negative electrode tab overlap each other in the stacking direction of the laminate, and the depression portion formed on the negative electrode and the positive electrode tab overlap each other can be nested.

A secondary battery according to an embodiment of the present invention includes the electrode assembly described above.

The method for manufacturing an electrode assembly according to an embodiment of the present invention includes the steps of preparing an electrode plate having a width and a length and having the length longer than the width, and forming a plurality of depressions on one side of the electrode plate in the longitudinal direction. , attaching a plurality of tapes spaced apart from each other to the electrode plate along one side parallel to one side of the electrode plate on which the plurality of depressions are formed, coating an electrode active material layer on the electrode plate, and the electrode plate and cutting to form a plurality of electrodes.

The electrode assembly manufacturing method may further include removing the plurality of tapes from the electrode plate or the electrode after coating the electrode active material layer on the electrode plate.

The tape may be removed to form an uncoated region on the electrode, the uncoated region may form an electrode tab, and an edge of the electrode tab may be formed to coincide with an edge of the electrode.

According to embodiments, by forming the electrode tab inside the electrode plate without protruding to the outside, it is possible to prevent the electrode tab from being folded during the manufacturing process of the electrode assembly and increase the capacity in a battery cell of the same size.

1 is a plan view showing an electrode plate according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the cutting line I-I' of FIG. 1 .
3 is a cross-sectional view illustrating an electrode assembly according to an embodiment of the present invention.
FIG. 4 is a plan view of the electrode assembly of FIG. 3 as viewed in the X direction of FIG. 2 .
5 is a plan view illustrating separation of each layer constituting the electrode assembly of FIG. 4 .
6 to 10 are plan views illustrating a method of manufacturing an electrode assembly according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in several different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of description, the present invention is not necessarily limited to the illustrated bar. In order to clearly express various layers and regions in the drawings, the thicknesses are enlarged. And in the drawings, for convenience of description, the thickness of some layers and regions are exaggerated.

Further, when a part of a layer, film, region, plate, etc. is said to be “on” or “on” another part, it includes not only cases where it is “directly on” another part, but also cases where another part is in between. . Conversely, when we say that a part is "just above" another part, we mean that there is no other part in the middle. In addition, to be "on" or "on" the reference part means to be located above or below the reference part, and to necessarily mean to be located "on" or "on" in the direction opposite to the gravity not.

In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

In addition, throughout the specification, when referring to "planar", it means when the target part is viewed from above, and "in cross-section" means when viewed from the side when a cross-section of the target part is vertically cut.

1 is a plan view showing an electrode plate according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the cutting line I-I' of FIG. 1 .

Referring to FIG. 1 , an electrode plate 101 constituting an electrode assembly according to an embodiment of the present invention is shown, and in this embodiment, the electrode plate 101 is an electrode 110 in which an electrode active material layer is coated on an electrode current collector. ) is included. The electrode 110 may be a positive electrode or a negative electrode, and the electrode 110 is connected to the electrode tab 50 made of an uncoated region on which the electrode active material layer is not coated. Referring to FIG. 2 in this regard, the electrode active material layer 100a is coated on the electrode current collector 100 to form the electrode 110, and the electrode current collector 100 on which the electrode active material layer 100a is not coated. A portion may form an electrode tab 50 . A portion where the electrode tab 50 is positioned has a thickness smaller than that of the electrode 110 .

Referring back to FIG. 1 , the electrode tab 50 is located in an edge region of the electrode plate 101 , and two protrusions 115p spaced apart from each other with respect to the electrode tab 50 are formed on the electrode 110 . .

As shown in the lower part of FIG. 1 , the line W connecting the ends of the two protrusions 115p spaced apart from each other may coincide with one side of the electrode tab 50 . Such structural features may appear as a result of the method for manufacturing an electrode assembly according to an embodiment of the present invention, which will be described later, which will be described in detail later.

In the electrode 110 according to the present embodiment, a depression 105 is formed on one side of the electrode 110 adjacent to the electrode tab 50 and the other side facing the other side. In the depression 105 , the electrode tabs of different electrodes and the electrode leads connected thereto are positioned to overlap each other, thereby preventing a short circuit due to contact between the different electrodes. The electrode 110 according to the present exemplary embodiment may have an “H” shape because it occupies a rectangular shape in which the depression 105 and the corresponding electrode tab 50 are excluded.

3 is a cross-sectional view illustrating an electrode assembly according to an embodiment of the present invention. FIG. 4 is a plan view of the electrode assembly of FIG. 3 as viewed in the X direction of FIG. 2 . 5 is a plan view illustrating separation of each layer constituting the electrode assembly of FIG. 4 .

Referring to FIG. 3 , the electrode assembly according to the present embodiment may include at least one basic unit in which the negative electrode 30 , the separator 20 , and the positive electrode 10 are sequentially stacked. The positive electrode 10 and the negative electrode 30 may each be formed of the electrode plate 101 described with reference to FIG. 1 , and the positive electrode 10 and the negative electrode 30 may include a positive electrode tab and a negative electrode tab, respectively.

Referring to FIGS. 4 and 5 , when viewed in the X direction of FIG. 3 , one side of the positive electrode 10 and one side of the negative electrode 30 have depressions 105a and 105b, respectively, and on the other side, respectively A positive electrode tab 50a and a negative electrode tab 50b are formed. In a laminate including the positive electrode 10 , the separator 20 , and the negative electrode 30 , the positive electrode tab 50a and the negative electrode tab 50b are located opposite to each other with respect to the center of the laminate. At this time, the depression 105a and the negative electrode tab 50b formed in the positive electrode 10 in the stacking direction of the laminate, that is, in the X direction of FIG. 3 , overlap each other, and the depression 105b formed in the negative electrode 30 and The positive electrode tabs 50a overlap each other.

A secondary battery may be formed using the electrode assembly described above.

6 to 10 are plan views illustrating a method of manufacturing an electrode assembly according to an embodiment of the present invention.

Referring to FIG. 6 , an electrode current collector 100 having a width (h) and a length and a length longer than the width (h) is prepared, and the electrode current collector 100 is taken along a longitudinal direction perpendicular to the width (h) direction. A plurality of depressions 105 are formed on one edge of the The electrode current collector 100 is not particularly limited as long as it has high conductivity without causing chemical change in a battery including the electrode assembly according to the present embodiment, for example, copper, stainless steel, aluminum, nickel, Titanium, fired carbon, aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. may be used.

Referring to FIG. 7 , at the other edge of the electrode current collector 100 corresponding to one edge of the electrode current collector 100 in which the plurality of depressions 105 are formed, to correspond to each of the plurality of depressions 105 . A plurality of tapes 40 are attached. The plurality of tapes 40 have a rectangular shape and are positioned to be spaced apart from each other.

Referring to FIG. 8 , the electrode active material layer 100a is coated along the length direction of the electrode current collector 100 . In the case of forming a positive electrode, the electrode active material layer 100a includes a positive electrode active material, and the positive electrode active material is a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or one or more transition metals. compound, formula Li _1+y Mn _2-y O ₄ (where y is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ Lithium manganese oxide, lithium copper oxide (Li ₂ CuO ₂ ) , LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ , Vanadium oxide such as Cu ₂ V ₂ O ₇ , Formula LiNi _1-y M _y O ₂ (where M=Co, Mn, Al, Cu, Fe , Mg, B or Ga, and y=0.01 to 0.3 Ni site-type lithium nickel oxide, with the formula LiMn _2-y M _y O ₂ (where M=Co, Ni, Fe, Cr, Zn or Ta) and y=0.01 to 0.1) or Li ₂ Mn ₃ MO ₈ (wherein, M=Fe, Co, Ni, Cu or Zn) Lithium manganese composite oxide, in which part of Li in the formula is substituted with alkaline earth metal ions LiMn ₂ O ₄ , a disulfide compound, Fe ₂ (MnO ₄ ) ₃ , etc., but is not limited thereto. In this case, the electrode active material layer 100a may be prepared by applying a positive electrode mixture including a mixture of the positive electrode active material, a conductive material, and a binder to the electrode current collector 100, drying and pressing, and, if necessary, to the mixture. Additional fillers may be added.

When the negative electrode is formed by coating the electrode active material layer 100a along the longitudinal direction of the electrode current collector 100, the electrode active material layer 100a includes a negative electrode active material, and the negative electrode active material is non-graphitized carbon, graphite-based carbon carbon, such as Li _x FeO ₃ (0≤x≤1), Li _x WO ₂ (0≤x≤1), Sn _x Me _1-x Me' _y O _z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of Groups 1, 2, and 3 of the periodic table, halogen; 0≤x≤1; 1≤y≤3; 1≤z≤8) metal composite oxide, lithium Metal, lithium alloy, silicon alloy, tin alloy, SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO ₂ , Bi ₂ O ₃ , Bi ₂ A metal oxide such as O ₄ or Bi ₂ O ₅ , a conductive polymer such as polyacetylene, or a Li-Co-Ni-based material may be used. In this case, the electrode active material layer 100a may be prepared by applying a negative electrode mixture including a mixture of the negative electrode active material, a conductive material, and a binder to the electrode current collector 100, drying and pressing, and, if necessary, to the mixture. Additional fillers may be added.

Referring to FIG. 9 , the uncoated region forming the electrode tab 50 not covered by the electrode active material layer 100a is formed by removing the tape 40 attached to the electrode current collector 100 , and connected to the electrode tab 50 . An electrode plate 101 including an electrode 110 is formed. At this time, since the electrode tab 50 is formed on the electrode current collector 100 covered with the tape 40 of FIG. 8 , the uncoated region may be connected to the electrode active material layer 100a, and one edge of the electrode active material layer 100a and One outer side of the electrode tab 50 may coincide with each other. The step of removing the tape 40 of FIG. 8 is not necessarily performed at this stage, and may be performed after the cutting step to be described later.

Referring to FIG. 10 , the electrode plate 101 is cut along the cut line A-A' and the cut line B-B' to form a plurality of electrode plates 101 including the electrodes 110 shown in FIG. 1 . When cutting, a cutting line may be set between the adjacent depressions 105 based on the previously formed depressions 105 .

As in this embodiment, since the electrode tab does not protrude from the electrode plate, when realizing a secondary battery having a compact structure, the electrode tab is formed in both sides of the concave portion of the protruding structure compared to the existing structure in which the electrode tab protrudes. High voltage, high capacity, etc. can be achieved as much as the protrusion part. Also, when rolling after coating the active material on the electrode current collector, in the case of the existing structure, the degree of elongation of the electrode current collector is different in the coated and uncoated parts, which causes camber, which can be a problem during cutting and precision matching assembly. , According to this embodiment, it is possible to prevent the occurrence of camber due to the difference in the amount of elongation occurring between the coated portion and the uncoated portion during rolling. In addition, in the case of an existing structure while driving for assembly, there are problems such as electrode tab jamming and folding, but these problems can be prevented according to the present embodiment.

Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the

40: tape
50: electrode tab
101: electrode plate
105, 105a, 105b: depressions
115p: overhang

Claims (10)

an electrode plate comprising an electrode connected to an electrode tab, wherein the electrode tab is an uncoated region positioned at an edge region of the electrode plate, and the uncoated region is integrally formed with the electrode,
The electrode includes two protrusions spaced apart from each other with respect to the electrode tab, and a line connecting the ends of the two protrusions coincides with one side of the electrode tab. delete In claim 1,
An electrode assembly in which a depression is formed on one side of the electrode adjacent to the electrode tab and the other side facing the other side. In claim 1,
The electrode assembly has an “H” shape. In claim 1,
The electrode plate is formed in plurality, the electrode plate formed in plurality includes a positive electrode and a negative electrode, a separator is positioned between the positive electrode and the negative electrode, and the positive electrode and the negative electrode each include a positive electrode tab and a negative electrode tab, and the positive electrode , In the laminate including the separator and the negative electrode, the positive electrode tab and the negative electrode tab are located opposite to each other with respect to the center of the laminate. In claim 5,
A depression portion is formed on one side of the positive electrode and one side of the negative electrode, respectively, the depression portion formed on the positive electrode and the negative electrode tab overlap each other in the stacking direction of the laminate, and the depression portion formed on the negative electrode and the positive electrode tab overlap each other Overlapping electrode assemblies. A secondary battery comprising the electrode assembly of any one of claims 1 and 3 to 6 . having a width and a length, and preparing an electrode plate having a length longer than the width;
forming a plurality of depressions on one side of the electrode plate in the longitudinal direction;
attaching a plurality of tapes spaced apart from each other to the electrode plate along another side parallel to one side of the electrode plate on which the plurality of depressions are formed;
coating an electrode active material layer on the electrode plate;
removing the plurality of tapes from the electrode plate or the electrode; and
Comprising the step of forming a plurality of electrodes by setting a cutting line between the recessed parts adjacent to each other based on the previously formed recessed part, and cutting the electrode plate along the cutting line,
In the step of removing the plurality of tapes from the electrode plate or the electrode, the tape is removed to form an uncoated area on the electrode, the uncoated area forms an electrode tab, and the electrodes are spaced apart from the electrode tab. A method of manufacturing an electrode assembly including four protrusions, wherein a line connecting the ends of the two protrusions coincides with one side of the electrode tab. delete delete

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