KR102082655B1 - Method Preparing Electrode Assembly Having Corner Cutting Structure and Electrode Assembly Prepared Using the Same - Google Patents

Abstract

The present invention relates to a method for manufacturing an electrode assembly having a corner-cut structure and an electrode assembly manufactured using the same, and more particularly, to a method for manufacturing an electrode assembly having a structure in which a separator is interposed between an anode and a cathode. (a) preparing an electrode stack having a positive electrode and a negative electrode each of which one or more corners are cut out, and a separator between the positive electrode and the negative electrode; (b) mounting the electrode stack on a first heat fusion plate having a heat fusion support portion protruding upwardly corresponding to the cut edges of the anode and the cathode; (c) heat-sealing the separators by lowering the second heat-fusion plate to heat-bond the portions of the separators positioned on the heat-sealing support; And (d) cutting the inner ends of the separators cured by thermal fusion.

Description

Method for manufacturing electrode assembly with cut edge and electrode assembly manufactured using the same {Method Preparing Electrode Assembly Having Corner Cutting Structure and Electrode Assembly Prepared Using the Same}

The present invention relates to a method for manufacturing an electrode assembly having a cut edge and an electrode assembly manufactured using the same.

Recently, secondary batteries capable of charging and discharging have been widely used as energy sources of wireless mobile devices. In addition, secondary batteries are attracting attention as energy sources such as electric vehicles and hybrid electric vehicles, which are proposed as a way to solve air pollution of conventional gasoline and diesel vehicles using fossil fuel. Therefore, the type of applications using the secondary battery is very diversified due to the advantages of the secondary battery, and it is expected that the secondary battery will be applied to many fields and products in the future.

Such secondary batteries may be classified into lithium ion batteries, lithium ion polymer batteries, lithium polymer batteries, etc. according to the composition of the electrode and the electrolyte, and among them, there is little possibility of leakage of the electrolyte and the amount of lithium ion polymer batteries that are easy to manufacture is high. Growing. In general, the secondary battery is a cylindrical battery and a rectangular battery in which the electrode assembly is embedded in a cylindrical or rectangular metal can, and a pouch type battery in which the electrode assembly is embedded in a pouch type case of an aluminum laminate sheet according to the shape of the battery case. The electrode assembly embedded in the battery case is composed of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode is capable of charging and discharging, between the long sheet type positive electrode and the negative electrode coated with the active material It is classified into a jelly-roll type wound through a separator and a stack type in which a plurality of positive and negative electrodes of a predetermined size are sequentially stacked in a state interposed in the separator.

Among these, due to the high capacity of the battery, a large area of the case and processing into a thin material have attracted much attention, and thus, a structure in which a stack type or a stack / fold type electrode assembly is incorporated in a pouch type battery case of an aluminum laminate sheet Pouch-type batteries have gradually increased due to low production cost, small weight, and easy shape deformation.

Recently, a new type of battery cell is required due to the slim type or various design trends, and the shape of the electrode assembly housed inside the battery case to make a new structure in consideration of the limited space of the device to which the battery cell is applied. The battery cell of the structure which cut | disconnected a part site | part was manufactured by making the change.

1 is a schematic diagram of a conventional pouch type secondary battery.

Referring to FIG. 1, the pouch type secondary battery 10 includes an electrode assembly 30 having a positive electrode, a negative electrode, and a separator disposed therebetween inside the pouch type battery case 20. The two electrode leads 40 and 41 electrically connected to 31 and 32 are sealed to be exposed to the outside.

The battery case 20 is composed of a case body 21 including a recess 23 having a concave shape in which the electrode assembly 30 can be seated, and a cover 22 integrally connected to the body 21. have.

The battery case 20 is made of a laminate sheet, and is composed of an outer resin layer 20A forming an outermost shell, a barrier metal layer 20B for preventing penetration of a material, and an inner resin layer 20C for sealing. .

In the stacked electrode assembly 30, a plurality of positive electrode tabs 31 and a plurality of negative electrode tabs 32 are fused to each other and coupled to the electrode leads 40 and 41. In addition, in order to prevent shorts from occurring when the upper end 24 of the case body 21 and the upper end of the cover 22 are heat-sealed, the insulating film 50 is attached to the upper and lower surfaces of the electrode leads 40 and 41. do.

2 is a schematic diagram of a conventional membrane cutting process.

Referring to FIG. 2, after the electrode stack 33 is mounted on the die 70 and fixed with the pressure pad 60, the separators 25 are cut by the punch 65.

However, in the case of the manufacturing process, a burr such as a burr (FIG. 6; 27) is generated on the cutting surfaces of the separation membranes in the process of cutting the separation membranes to correspond to the outer shape of the battery case so that the cutting surface is not smooth.

In addition, the electrodes may be damaged by the pressing force of the punch in the process of cutting the separation membranes, which may cause deterioration of quality and shorten the life of the battery.

The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

Specifically, an object of the present invention is to solve the problem caused by not cutting the separators in the process of cutting the separators, the inside of the separators cured by heat-sealing the separators in the electrode laminate is cut edges It is to provide an electrode assembly manufacturing method comprising the step of cutting the end.

According to the present invention, a method for manufacturing an electrode assembly having a corner cut out according to the present invention, and an electrode assembly manufactured using the same,

A method of manufacturing an electrode assembly having a structure in which a separator is interposed between an anode and a cathode,

(a) preparing an electrode stack having a positive electrode and a negative electrode each of which one or more corners are cut out, and a separator between the positive electrode and the negative electrode;

(b) mounting the electrode stack on a first heat fusion plate having a heat fusion support portion protruding upwardly corresponding to the cut edges of the anode and the cathode;

(c) heat-sealing the separators by lowering the second heat-fusion plate to heat-bond the portions of the separators positioned on the heat-sealing support; And

(d) cutting the inner ends of the separators cured by thermal fusion;

It is configured to include.

That is, the electrode assembly manufacturing method and the electrode assembly manufactured using the structure of the corner is cut in accordance with the present invention, the cutting is performed after the heat-sealing the separators in the process of cutting the separators to correspond to the appearance of the battery case, cutting after curing The workability can be improved, and the damage of the electrode terminals can be prevented to improve the safety of the battery cell.

According to the present invention, before the step (a), (i) applying an electrode mixture containing an electrode active material to each of the positive electrode sheet and the negative electrode sheet; And (ii) cutting at least one corner portion at the same position in the positive electrode sheet and the negative electrode sheet.

In one specific example, the cutting edges in the positive electrode and the negative electrode may have a structure in which two electrode outer peripheries crossing each other are indented inwardly at the edges.

For example, sidewalls of a shape corresponding to the outer periphery of the electrode stack may be formed in the first heat-sealed plate to form an indentation for mounting the electrode stack.

In this case, the heat fusion support may be located in the indentation while being integrally formed on the sidewall of the first heat fusion plate.

In other cases, the thermal fusion support may be coupled within the indentation of the first thermal fusion plate as a separate member.

In one specific example, the height of the heat fusion support may be 50% to 100% in size, specifically 60% to 99% in size and more specifically 70% to 95% in size of the sidewall height of the first heat fusion plate. .

According to the present invention, the second heat fusion plate may be formed with a heat fusion pressing portion at a portion corresponding to the heat fusion support of the first heat fusion plate.

In another case, the second heat fusion plate may have a flat surface facing the battery case.

In the above structure, the first heat fusion plate may include a heating unit for heating the separators to heat fusion.

In this structure, the second heat fusion plate may include a heating unit for heating the separators to heat fusion.

In one specific example, in the electrode assembly, electrodes are stacked in a height direction based on a plane, and a stepped step shape having different areas may be formed.

In this structure, the first heat fusion plate may be formed with a stepped heat fusion support part corresponding to the stepped stepped shape.

According to the present invention, the electrode assembly may have a stacked structure or a stack / foldable structure.

The present invention also provides a battery cell in which the electrode assembly prepared by the above method is built in the battery case,

A battery case comprising a first case and a second case and having an accommodating portion corresponding to a shape of the electrode assembly for mounting the electrode assembly on at least one of the first case and the second case;

Positive lead and negative lead protruding to the outside of the battery case; And

An electrode assembly accommodated in the battery case and having electrode tabs protruding from the battery case and having electrode lead-electrode tab coupling portions formed thereon, wherein electrode tabs of the electrode plates are coupled to the anode lead and the cathode lead;

It contains,

The battery case provides a battery cell having a structure in which at least one corner is indented based on the plane.

In one specific example, the battery case may be made of a laminate sheet including a resin layer and a metal layer.

The present invention also provides a battery pack including a battery cell.

The present invention also provides a device including a battery pack as a power source.

The device may be a computer, a mobile phone, a wearable electronic device, a power tool, an electric vehicle (EV), a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric motorcycle, an electric golf cart, or a system for power storage. Or the like.

Since the structure and fabrication method of such a device are known in the art, detailed description thereof will be omitted herein.

As described above, the electrode assembly manufacturing method and the electrode assembly manufactured by using a corner cut structure according to the present invention, in order to solve the problems caused by the non-uniform cutting surface in the process of cutting the separation membrane Since the separators are thermally fused and cured and then cut, the manufacturing processability can be improved.

In addition, by preventing the damage of the electrode terminals by the pressing force of the punch for punching the separation membrane provides an effect that can improve the safety of the battery cell.

1 is a schematic view of a pouch type secondary battery including a conventional electrode assembly;
2 is a schematic diagram of a conventional membrane cutting process;
3 is a schematic diagram of an electrode assembly with a cut edge in accordance with one embodiment of the present invention;
4 is a schematic diagram showing a first heat-sealed plate according to one embodiment of the present invention;
FIG. 5 is a schematic diagram showing a structure of thermally fusion bonding a first heat fusion plate of FIG. 4 with a second heat fusion plate; FIG.
6 is a schematic diagram comparing a cross section of a conventional separator and a cross section according to the present invention;
7 is a schematic view of an electrode assembly having a stepped stepped shape and a corner cut out according to another embodiment of the present invention;
FIG. 8 is a schematic diagram of a heat fusion plate in which a heat fusion support is formed at a corresponding portion of a site where a stepped step of FIG. 7 is formed; FIG.
9 is a flowchart illustrating a method of manufacturing an electrode assembly having a corner cut out according to an embodiment of the present invention.

Hereinafter, although described with reference to the drawings according to an embodiment of the present invention, this is for easier understanding of the present invention, the scope of the present invention is not limited thereto.

Figure 3 is a schematic diagram of a method for manufacturing an electrode assembly is cut corners according to an embodiment of the present invention.

Referring to FIG. 3, the first electrode assembly 100 having a corner cut structure according to an embodiment of the present invention includes anodes and cathodes in which each corner 150 is cut and vertically stacked. 131 and the electrode stack 110 having the separators 140 interposed between the anodes and the cathodes 131. The separators 140 are interposed in a rectangular shape including the edges 150 of the anodes and the cathodes 131.

Each of the stacked positive and negative electrodes 131 is composed of rectangular outer peripheries 131a, 131b, 131c, and 131d, and the cut edges 150 are perpendicular to each other at opposite sides of the positive and negative electrode tabs 120 and 130. Two electrode outer peripheries 131a and 131b intersecting each other are indented inward toward the center of the electrode plate.

The positive and negative electrode tabs 120 and 130 are coupled to the positive lead and the negative electrode lead (not shown) by the electrode lead-electrode tab coupling.

Figure 4 is a schematic diagram showing a first heat-sealed plate according to an embodiment of the present invention.

Referring to FIG. 4, the first electrode stack (1) may be formed on the first heat fusion plate 200, in which the heat fusion support 250 having a shape corresponding to the cut edges of the anode and the cathode (FIG. 3: 150) protrudes upward. 3: seat 110).

In order to form the indentation 210 for mounting the first electrode stack 110 on the first heat-sealing plate 200, sidewalls having a shape corresponding to the outer periphery of the first electrode stack 110 ( 230 is formed.

The heat welding support part 250 is positioned in the indentation part 210 while being integrally formed on the sidewalls 230 of the first heat welding plate 200. When the heat fusion support 250 is a structure that is coupled within the indentation 210 of the first heat fusion plate 200 as a separate member can be adjusted the number and height of the cutting edge.

FIG. 5 is a schematic diagram illustrating a structure in which the first heat welding plate of FIG. 4 is heat-sealed with a second heat welding plate.

Referring to FIG. 5, a cross-sectional view taken along the line AA ′ of FIG. 4 is shown. The height H ₂ of the heat fusion support part 250 of the first heat fusion plate 200 is 95% of the side wall height H ₁ of the first heat fusion plate 200, specifically, 60% to 99%. Size, more specifically 70% to 95% in size.

Sidewalls 230 are formed at the outer circumference of the first heat-sealed plate 200 such that the indentation 210 is located inside.

The second heat fusion plate 300 has a heat fusion press portion 350 formed at a portion corresponding to the heat fusion support portion 250 of the first heat fusion plate 200, so that the second heat fusion plate 300 may press on the correct portions of the heat fusion separators. have.

The second heat fusion plate 300 includes a heating part 360 that heats the separation membranes to heat fusion. The second heat fusion plate 300 is lowered toward the first heat fusion plate 200, and the heat fusion press part 350 faces the heat fusion support part 250 to thermally seal the separators. The second heat fusion plate 300 has a flat surface facing the electrode stack.

6 is a schematic diagram comparing the cross section of the conventional separator and the cross section according to the present invention.

Referring to FIG. 6, scratches, such as burs 27, are generated on the cutting surfaces of the conventional separation membranes 25 so that the cutting surfaces are not smooth. When the separators 140 are cut according to the present invention, the separators 140 are cut in a uniform cutting surface as shown by the arrow direction.

7 is a schematic diagram of a method for manufacturing an electrode assembly, in which a stepped step shape is formed and a corner thereof is cut out according to another embodiment of the present invention.

Referring to FIG. 7, in the second electrode assembly 101, electrodes 133 are stacked in a height direction with respect to a plane, and stepped steps having different areas are formed.

The second electrode assembly 101 includes a second electrode stack 111 having a stepped shape having a different area, and is overlapped since the stepped edge 151 is formed in a stepped stepped structure. The description will be omitted.

FIG. 8 is a schematic view of a third heat fusion plate in which a third heat fusion support is formed with respect to a portion where the stepped step of FIG. 7 is formed.

Referring to FIG. 8, the third heat fusion plate 201 has a third heat fusion stepped shape corresponding to a stepped edge (FIG. 7: 151) formed in the second electrode assembly (FIG. 7: 101). The support part 251 is formed.

9 is a flowchart illustrating a method of manufacturing an electrode assembly having a corner cut out according to an embodiment of the present invention.

Referring to FIG. 9, a method of manufacturing an electrode assembly having a separator interposed between a positive electrode and a negative electrode, comprising: (a) positive and negative electrodes each having one or more corners cut out, and a rectangle between the positive and negative electrodes; An electrode laminate is prepared through the separator (S110). (b) The electrode stack is seated on a first heat-sealing plate having sidewalls of a shape corresponding to the outer periphery of the electrode stack, and a heat-sealing support of a shape corresponding to the cut edges of the anode and cathode. (S120). (c) In order to thermally fusion the portions of the separation membranes positioned in the thermal fusion support, the second thermal fusion plates corresponding to the first thermal fusion plates are lowered to thermally bond the separation membranes (S130). (D) the inner end of the separators cured by thermal fusion, that is, the outer periphery of the electrode is cut along the outer periphery indented in the corner (S140).

Before the process (a), (i) the electrode mixture containing the electrode active material is applied to the positive electrode sheet and the negative electrode sheet, respectively. (ii) Cut at least one corner at the same position with respect to the plane in the positive electrode sheet and the negative electrode sheet.

Those skilled in the art 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 contents.

Claims (18)

A method of manufacturing an electrode assembly having a structure in which a separator is interposed between an anode and a cathode,
(a) preparing an electrode stack having a positive electrode and a negative electrode each of which one or more corners are cut out, and a separator between the positive electrode and the negative electrode;
(b) mounting the electrode stack on a first heat fusion plate having a heat fusion support portion protruding upwardly corresponding to the cut edges of the anode and the cathode;
(c) heat-sealing the separators by lowering the second heat-fusion plate to heat-bond the portions of the separators positioned on the heat-sealing support; And
(d) cutting the inner ends of the separators cured by thermal fusion;
Electrode assembly manufacturing method comprising a. The method of claim 1, wherein before the step (a),
(i) applying an electrode mixture including an electrode active material to the positive electrode sheet and the negative electrode sheet, respectively; And
(ii) cutting at least one corner portion at the same position in the positive electrode sheet and the negative electrode sheet;
Electrode assembly manufacturing method comprising a further. The method of claim 1, wherein the cutting edges in the positive electrode and the negative electrode is a manufacturing method of the electrode assembly, characterized in that the outer periphery of the two electrodes intersecting each other indented inward at the corner. According to claim 1, wherein the first heat-sealing plate, in order to form an indentation for the mounting of the electrode stack, the electrode assembly manufacturing, characterized in that the side wall of the shape corresponding to the outer periphery of the electrode stack is formed Way. The electrode assembly manufacturing method of claim 4, wherein the heat-sealing support part is positioned in the indentation while being integrally formed on the side wall of the first heat-sealing plate. 5. The method of claim 4, wherein the heat fusion support is coupled as an additional member in the indentation of the first heat fusion plate. 5. The method of claim 4, wherein the height of the heat fusion support is 50% to 100% of the height of the side wall of the first heat fusion plate. The electrode assembly manufacturing method according to claim 1, wherein the second heat fusion plate has a heat fusion press portion formed at a portion corresponding to the heat fusion support of the first heat fusion plate. The electrode assembly manufacturing method of claim 1, wherein the second heat-sealing plate has a flat surface facing the battery case. The electrode assembly manufacturing method of claim 1, wherein the first heat fusion plate includes a heating unit configured to heat the separators to heat fusion the separators. The electrode assembly manufacturing method of claim 1, wherein the second heat fusion plate includes a heating unit configured to heat the separators to heat fusion the separators. The method of claim 1, wherein the electrode assembly has electrodes stacked in a height direction based on a plane, and a stepped step having a different step area is formed. The electrode assembly manufacturing method according to claim 12, wherein the first heat fusion plate is formed with a stepped heat fusion support part corresponding to the stepped step. The method of claim 1, wherein the electrode assembly has a stacked structure or a stack / foldable structure. A battery cell in which an electrode assembly manufactured by the method according to any one of claims 1 to 14 is embedded in a battery case,
A battery case comprising a first case and a second case and having an accommodating portion corresponding to a shape of the electrode assembly for mounting the electrode assembly on at least one of the first case and the second case;
Positive lead and negative lead protruding to the outside of the battery case; And
An electrode assembly accommodated in the battery case and having electrode tabs protruding from the battery case and having electrode lead-electrode tab coupling portions formed thereon, wherein electrode tabs of the electrode plates are coupled to the positive lead and the negative lead;
It contains,
In the battery case is characterized in that the battery cell is characterized in that the at least one corner is indented inwardly structure based on the plane ,
The electrode assembly has a structure in which at least one corner is indented inwardly, the separator of the inwardly indented corner is cut after curing by heat fusion. The battery cell according to claim 15, wherein the battery case is formed of a laminate sheet including a resin layer and a metal layer. A battery pack comprising a battery cell according to claim 15. A device comprising the battery pack according to claim 17 as a power source.

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