KR20170072487A - 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 of manufacturing an electrode assembly having a corner cut-off structure and an electrode assembly manufactured using the same, and more particularly, to a method of manufacturing an electrode assembly having a separator interposed between an anode and a cathode, (a) preparing positive electrode and negative electrode, each of which has at least one edge cut off, and an electrode stack between the positive electrode and the negative electrode via a separation membrane; (b) placing the electrode laminate on a first heat-sealing plate having upwardly protruding heat-sealing support portions of a shape corresponding to cut edges of the positive electrode and the negative electrode; (c) lowering the second heat-sealing plate to thermally fuse the portions of the separation membranes located in the heat-sealing support portion; And (d) cutting the inner end of the separation membranes cured by thermal welding.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing an electrode assembly having a corner cut-off structure and an electrode assembly manufactured using the same,

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

BACKGROUND ART [0002] In recent years, rechargeable secondary batteries have been widely used as energy sources for wireless mobile devices. In addition, the secondary battery is attracting attention as an energy source for electric vehicles, hybrid electric vehicles, and the like, which is proposed as a solution for air pollution in existing gasoline vehicles and diesel vehicles using fossil fuels. Therefore, the types of applications using secondary batteries are diversifying due to the advantages of secondary batteries, and it is expected that secondary batteries will be applied to many fields and products in the future.

Such a secondary battery may be classified as a lithium ion battery, a lithium ion polymer battery, or a lithium polymer battery depending on the configuration of an electrode and an electrolytic solution. The amount of the lithium ion polymer battery Is growing. 2. Description of the Related Art Generally, a secondary battery includes a cylindrical battery and a prismatic battery in which an electrode assembly is embedded in a cylindrical or rectangular metal can according to the shape of a battery case, and a pouch type battery in which an electrode assembly is embedded in a pouch- , And an electrode assembly embedded in the battery case is a power generation device that includes a positive electrode, a negative electrode, and a separator structure sandwiched between the positive electrode and the negative electrode, and is capable of charging and discharging. The electrode assembly includes a long sheet-like positive electrode coated with an active material, A jelly-roll type which is wound with a separator interposed therebetween, and a stacked type in which a plurality of positive electrodes and negative electrodes of a predetermined size are sequentially stacked with a separator interposed therebetween.

Among them, due to the high capacity of the battery, enlargement of the size of the case and the processing of a thin material are attracting much attention. Accordingly, a stacked or stacked / folded type electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet The pouch-shaped battery of the present invention has been gradually increased in usage due to low manufacturing cost, small weight, and easy shape deformation.

In recent years, a new type of battery cell is required due to a slim type or various design trends. In order to make a new structure in consideration of a limited space of a device to which a battery cell is applied, a shape of an electrode assembly A battery cell having a structure in which a part is cut is manufactured.

1 is a schematic view of a conventional pouch-type secondary battery.

Referring to FIG. 1, the pouch type secondary battery 10 includes an electrode assembly 30 including an anode, a cathode, and a separator disposed between the anode and the cathode, 31 and 32 are sealed to be exposed to the outside.

The battery case 20 includes a case body 21 including a concave shaped storage portion 23 on 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 laminated sheet and is composed of an outer resin layer 20A forming an outermost layer, a barrier metal layer 20B 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. An insulating film 50 is attached to the upper and lower surfaces of the electrode leads 40 and 41 in order to prevent a short circuit from occurring when the upper end 24 of the case body 21 and the upper end of the cover 22 are thermally fused. do.

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

2, after the electrode stack 33 is mounted on the die 70 and fixed with the pressure pad 60, the separators 25 are cut with the punch 65. As shown in Fig.

However, in the process of manufacturing the separator according to the above-described manufacturing process, scratches such as burrs (FIG. 6) are generated on the cut surfaces of the separators in the process of cutting the separators to correspond to the outer shape of the battery case.

In addition, in the process of cutting the separators, the electrodes may be damaged by the pressing force of the punches, thereby deteriorating the quality and shortening the life of the battery.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

More specifically, the present invention has been made to solve the problem that cutting of the separators is not performed smoothly in the course of cutting the separators, and it is an object of the present invention to provide a separator, And cutting the end portion of the electrode assembly.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, a method of manufacturing an electrode assembly having a corner cut-

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

(a) preparing positive electrode and negative electrode, each of which has at least one edge cut off, and an electrode stack between the positive electrode and the negative electrode via a separation membrane;

(b) placing the electrode laminate on a first heat-sealing plate having upwardly protruding heat-sealing support portions of a shape corresponding to cut edges of the positive electrode and the negative electrode;

(c) lowering the second heat-sealing plate to thermally fuse the portions of the separation membranes located in the heat-sealing support portion; And

(d) cutting the inner end of the separators cured by thermal welding;

.

That is, the method of manufacturing an electrode assembly having a corner cut-off structure according to the present invention and the electrode assembly manufactured using the same have a feature in that, in the process of cutting the separators corresponding to the outer shape of the battery case, The processability can be improved and damage to the electrode terminals can be prevented, so that the safety of the battery cell can be improved.

According to the present invention, before step (a), (i) a process of applying an electrode mixture containing an electrode active material to a positive electrode sheet and a negative electrode sheet, respectively; And (ii) cutting one or more corners at the same position in the positive electrode sheet and the negative electrode sheet.

In one specific example, the cut corners in the positive electrode and the negative electrode may be a structure in which two outer electrode peripheries intersecting with each other are indented inward at an edge.

For example, a sidewall having a shape corresponding to the outer periphery of the electrode stacked body may be formed on the first thermal fuse plate so as to form an indentation for seating the electrode stacked body.

In this case, the heat-fusing support portion may be located in the indent portion in a state of being integrally formed on the side wall of the first heat-fusing plate.

In other cases, the heat-fusing support may be joined as a separate member within the indentation of the first heat-fusing plate.

In one specific example, the height of the thermally welded support may be 50% to 100% of the height of the sidewall of the first thermally welded plate, specifically 60% to 99% of the height, more specifically 70% to 95% .

According to the present invention, the second fusion splicing plate may be provided with a thermal fusion splicing portion at a portion corresponding to the thermal fusion splicing portion of the first fusion splicing plate.

In other cases, the second heat fusing plate may have a flat surface facing the battery case.

In the above structure, the first heat-sealing plate may include a heating unit for heating the heat-dissipating films to heat-seal the first heat-sealing plate.

In this structure, the second heat fusion plate may include a heating portion for heating the separation membranes so as to be thermally fused.

In one specific example, the electrode assembly may be formed such that the electrodes are stacked in the height direction with respect to the plane, and stepped steps having different areas are formed.

In such a structure, the first heat fusion plate may be provided with a step-shaped heat-welded support portion corresponding to the stepped step.

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

The present invention also provides a battery cell in which an electrode assembly manufactured by the above method is embedded in a battery case,

A battery case having a first case and a second case, wherein at least one of the first case and the second case has a housing part corresponding to the shape of the electrode assembly for mounting the electrode assembly;

A positive electrode lead and a negative electrode lead protruding outside the battery case; And

An electrode assembly that is accommodated in the battery case and has electrode tabs projecting from the battery case and electrode tabs of the electrode plates are coupled to the positive electrode lead and the negative electrode lead;

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The battery case has a structure in which at least one corner is inwardly recessed with respect to a plane.

In one specific example, the battery case may be formed 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, a motorcycle, And the like.

The structure and manufacturing method of such a device are well known in the art, so a detailed description thereof will be omitted herein.

As described above, the method for manufacturing an electrode assembly having a corner cut-off structure according to the present invention and the electrode assembly manufactured using the method are effective for solving the problems caused by the uneven cutting surface in the process of cutting the separators The separation membranes are thermally fused and cured and then cut, so that the manufacturing processability can be improved.

Also, it is possible to prevent the electrode terminals from being damaged by the pressing force of the punch for punching the separation membranes, thereby improving the safety of the battery cells.

1 is a schematic view of a pouch type secondary battery including a conventional electrode assembly;
2 is a schematic view of a conventional membrane cutting process;
3 is a schematic illustration of an edge-cut electrode assembly according to one embodiment of the present invention;
4 is a schematic view showing a first heat fusing plate according to one embodiment of the present invention;
5 is a schematic view showing a structure in which the first heat welding plate of FIG. 4 is thermally welded to the second heat welding plate;
6 is a schematic diagram for comparing the cross-section of a conventional separation membrane and the cross-section according to the present invention;
7 is a schematic view of an electrode assembly in which stepped steps are formed and edges are cut according to another embodiment of the present invention;
FIG. 8 is a schematic view of a heat-welding plate in which a heat-welding support portion is formed at a corresponding portion of a portion where the stepped step is formed in FIG. 7; FIG.
9 is a flowchart of a method of manufacturing an electrode assembly having a corner cut-off structure according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

FIG. 3 is a schematic view of a method of manufacturing an electrode assembly in which corners are cut according to an embodiment of the present invention.

Referring to FIG. 3, a first electrode assembly 100 having a corner cut-off structure according to an embodiment of the present invention includes anodes and cathodes 150, each of which is cut off and vertically stacked, And an electrode stack body 110 in which separating films 140 are interposed between the anodes and the cathodes 131. The separators 140 are disposed in a rectangular shape including the anodes 150 and the corners 150 of 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 on the opposite sides of the anode and cathode taps 120, And the two intersecting outer circumferences 131a and 131b are inwardly directed toward the center of the electrode plate.

The anode and cathode taps 120 and 130 are coupled to the cathode lead and the cathode lead (not shown) by electrode lead-electrode tap bonding.

4 is a schematic view showing a first heat fusing plate according to an embodiment of the present invention.

Referring to FIG. 4, a first electrode stacking body (not shown) is formed on a first heat-sealing plate 200 having upwardly protruding heat-sealing support portions 250 of a shape corresponding to the cut edges of the positive electrode and the negative electrode 3: 110).

The first thermal fusing plate 200 may have sidewalls having a shape corresponding to the outer periphery of the first electrode stack 110 in order to form the indent 210 for seating the first electrode stack 110 230 are formed.

The thermal fusing support 250 is positioned in the recess 210 in a state where it is integrally formed with the side walls 230 of the first thermal fusing plate 200. The number and the height of the cutting edges can be adjusted in the case of a structure in which the heat-welding support portions 250 are coupled to the indentations 210 of the first heat-welding plates 200 as individual members.

Fig. 5 is a schematic view showing a structure in which the first heat fusing plate of Fig. 4 is thermally fused to the second heat fusing plate.

Referring to FIG. 5, a cross-sectional view taken along the line A-A 'of FIG. 4 is shown. The height H ₂ of the heat seal supporting portion 250 of the first heat seal plate 200 is 95% of the height H ₁ of the side wall of the first heat seal plate 200, specifically, 60% to 99% Size, more specifically 70% to 95% size.

The first thermal fusion plate 200 has sidewalls 230 formed on the outer periphery thereof so that the indentation 210 is located inside.

The second heat-sealing plate 300 is provided with a heat-sealing and pressing portion 350 at a portion corresponding to the heat-sealing and supporting portion 250 of the first heat-sealing plate 200 to pressurize the heat- have.

The second thermal fusion plate 300 includes a heating unit 360 for heating the separation membranes to be thermally fused. The second heat fusion plate 300 is lowered toward the first heat fusion plate 200 and the heat fusion pressing portion 350 faces the heat fusion support portion 250 to thermally fuse the separation membranes. The second thermal fusion plate 300 is a structure in which the surface facing the electrode laminate is flat.

FIG. 6 is a schematic view for comparing a cross section of a conventional separation membrane and a cross section according to the present invention.

Referring to FIG. 6, scratches such as burrs 27 are formed on the cutting surfaces of conventional separators 25, so that the cut surfaces are not smooth. When the separators 140 are cut according to the present invention, they are cut into uniform cut surfaces as shown by arrows.

7 is a schematic view of a method of manufacturing an electrode assembly in which stepped steps are formed and edges are cut according to another embodiment of the present invention.

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

The second electrode assembly 101 includes the second electrode stacked body 111 having a stepped shape with different areas and has the same structure except that the stepped edge 151 is formed in a stepped step structure. And the description thereof will be omitted.

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

Referring to FIG. 8, the third heat-sealing plate 201 is provided with a third heat-sealing process (not shown) corresponding to stepped stepped edges (FIG. 7: 151) formed in the second electrode assembly A support portion 251 is formed.

FIG. 9 is a flow chart of a method of manufacturing an electrode assembly having a corner cut-off structure according to an embodiment of the present invention.

Referring to FIG. 9, there is provided a method of manufacturing an electrode assembly having a separator interposed between an anode and a cathode, comprising the steps of: (a) forming an anode and an anode each having at least one edge cut off; An electrode stack is prepared through a separator (S110). (b) a sidewall having a shape corresponding to the outer periphery of the electrode stacked body is formed, and the electrode stack body is seated on the first heat fusion plate in which the heat fusion support portion of the shape corresponding to the cut edge of the anode and the cathode protrudes upward (S120). (c) In order to heat-seal the portions of the separation membranes located in the heat-sealing support portion, the rectangular second heat-sealing plate corresponding to the first heat-sealing plate is lowered to heat-seal the separation membranes (S130). (d) The inner ends of the membranes cured by the thermal fusion, that is, the outer periphery of the electrodes are cut along the outer periphery indented at the corners (S140).

Prior to the step (a), (i) an electrode mixture containing an electrode active material is applied to the positive electrode sheet and the negative electrode sheet, respectively. (ii) One or more corners are cut at the same position with respect to the plane in the positive electrode sheet and the negative electrode sheet.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

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 positive electrode and negative electrode, each of which has at least one edge cut off, and an electrode stack between the positive electrode and the negative electrode via a separation membrane;
(b) placing the electrode laminate on a first heat-sealing plate having upwardly protruding heat-sealing support portions of a shape corresponding to cut edges of the positive electrode and the negative electrode;
(c) lowering the second heat-sealing plate to thermally fuse the portions of the separation membranes located in the heat-sealing support portion; And
(d) cutting the inner end of the separators cured by thermal welding;
Wherein the electrode assembly includes a first electrode and a second electrode. The method according to claim 1, wherein, before the step (a)
(i) applying an electrode mixture containing an electrode active material to a positive electrode sheet and a 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;
Further comprising the steps of: The method of claim 1, wherein the two outermost edges of the anode and the cathode intersecting each other are cut out inward at the corners. The electrode assembly according to claim 1, wherein a side wall corresponding to an outer periphery of the electrode stack body is formed on the first heat fusion plate so as to form an indentation for seating the electrode stack body Way. The method of claim 4, wherein the heat-fusing support portion is located within the indent portion in a state where the heat-fusing support portion is integrally formed on the side wall of the first heat-fusing plate. 5. The method according to claim 4, wherein the heat-fusing support portion is coupled to the indented portion of the first heat-fusing plate as a separate member. 5. The method of claim 4, wherein the height of the heat-sealing support portion is 50% to 100% of the height of the side wall of the first heat-sealing plate. The method of manufacturing an electrode assembly according to claim 1, wherein the second thermal fusion plate is provided with a thermal fusion pressing portion at a portion corresponding to the heat fusion support portion of the first thermal fusion plate. The method of manufacturing an electrode assembly according to claim 1, wherein the second thermal fusion plate has a flat surface facing the battery case. The method of manufacturing an electrode assembly according to claim 1, wherein the first heat-sealing plate includes a heating unit for heating the separation membranes to be thermally fused. The method of manufacturing an electrode assembly according to claim 1, wherein the second heat-sealing plate includes a heating unit for heating the separation membranes to heat-seal them. The method according to claim 1, wherein the electrode assembly is formed by stacking electrodes in a height direction with respect to a plane and forming stepped steps having different areas. The method of manufacturing an electrode assembly according to claim 12, wherein the first heat-sealing plate is formed with a step-shaped heat-welded support portion corresponding to the stepped step. The method of claim 1, wherein the electrode assembly comprises a stacked structure or a stacked / folded structure. 14. 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 having a first case and a second case, wherein at least one of the first case and the second case has a housing part corresponding to the shape of the electrode assembly for mounting the electrode assembly;
A positive electrode lead and a negative electrode lead protruding outside the battery case; And
An electrode assembly that is accommodated in the battery case and has electrode tabs projecting from the battery case and electrode tabs of the electrode plates are coupled to the positive electrode lead and the negative electrode lead;
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Wherein the battery case has a structure in which at least one corner is indented inward with respect to a plane. 16. The battery cell according to claim 15, wherein the battery case comprises 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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