KR20110007547A - Electrode assembly for battery and manufacturing thereof - Google Patents

Abstract

PURPOSE: An electrode assembly for a battery is provided to prevent minute short caused by breakage generation of an electrode by minimizing cut parts of the electrode. CONSTITUTION: An electrode assembly for a battery includes a negative electrode plate(20) in which a plurality of layers are laminated by being formed in one body and folded; a positive electrode plate(10) laminated between layers of a plurality of negative electrode plates; and a separator(30) arranged between the negative electrode plate and the positive electrode plate.

Description

Electrode assembly for battery and manufacturing method thereof

The present invention relates to a battery electrode assembly and a method for manufacturing the same, and more particularly, to minimize the cutting portion of the electrode to prevent a short short caused by the occurrence of the electrode breakage, and to use in the manufacture of a lithium secondary battery It relates to a battery electrode assembly and a method of manufacturing the same that can improve the reliability.

Recently, various types of portable electronic devices using electric energy have been developed, and electric vehicles classified as eco-friendly vehicles as a means of transportation have been spotlighted, and batteries for storing and supplying electrical energy in connection with performance improvement of such portable electronic devices and electric vehicles. The performance problem of is highlighted. In particular, among the batteries used in such devices, a lithium secondary battery having a long life and excellent energy density per unit weight has attracted attention.

The lithium secondary battery is classified into a lithium ion battery using a liquid electrolyte and a lithium polymer battery using a polymer electrolyte according to the type of electrolyte. Among these, the lithium polymer battery has an advantage of relatively excellent stability and shape freedom of the battery, and consists of a structure in which a thin porous polymer separator is disposed between the electrode of the positive electrode and the negative electrode coated with the active material on the current collector.

In this case, the separator is an insulating thin film having high mechanical strength and ion permeability, and is configured to prevent electronic short circuits of the positive and negative electrodes and to serve as a path for insertion and desorption of lithium ions. .

In addition, the current collector is used for the positive electrode and the negative electrode, each of which is a highly conductive material, which is used separately in consideration of dissolution of materials by electrochemical side reactions. The commercially available form of the material is aluminum, stainless steel is used for the positive electrode, copper is applied for the cathode.

In this case, the positive and negative electrodes stacked with the separator interposed therebetween form an electrode group together with the positive and negative electrodes and the separator having a facing structure.

In addition to portable electronic devices and electric vehicles, secondary batteries including the lithium secondary batteries as described above are increasingly used for power sources and energy storage in solar power generation or wind power generation. Higher output and higher capacity than small secondary batteries used in IT field should be achieved.

Conventional battery electrode assemblies have been manufactured by winding an electrode composed of a positive electrode and a negative electrode in multiple layers with a seamless integrated separator therebetween, but it is difficult to make a large-sized and large-capacity battery by such a winding type manufacturing method.

Accordingly, in recent years, large- and large-capacity battery manufacturing has been gradually spreading by using a stacked type manufacturing method in which electrode plates composed of a plurality of positive electrode plates and negative electrode plates are alternately stacked with a separator interposed therebetween.

However, the conventional laminated electrode assembly manufacturing method alternately stacks a plurality of positive and negative plates cut to a predetermined size with a separator interposed therebetween, resulting in a slow production rate and damage due to the damage of the electrode mixture at the cutting site of the electrode. There is a possibility that a short occurs between the positive electrode and the negative electrode due to this.

Since the battery manufactured according to this is likely to cause quality problems, there is a need for a solution to solve the problem.

The present invention has been invented to solve the above problems, a single cathode plate which is folded and formed in multiple layers while being seamlessly developed is formed by being laminated with a plurality of positive electrode plates with a separator therebetween, thereby minimizing an electrode having a cut surface. It is an object of the present invention to provide a battery electrode assembly and a method of manufacturing the same, which can be manufactured in a high output and a large capacity while preventing fine shorts due to the occurrence of separation and increasing the reliability of the product.

The present invention to achieve the above object

A single negative electrode plate that is folded and stacked in a plurality of layers while unfolding as a single body; A positive electrode plate laminated between each layer of the negative electrode plate laminated in a plurality of layers; It provides a battery electrode assembly comprising a; separator disposed between the negative electrode plate and the positive electrode plate.

The present invention also provides a method for manufacturing an electrode assembly for a battery, wherein the negative electrode plate and the positive electrode plate are alternately stacked with the separator interposed therebetween, and the negative electrode plate is folded and folded in a plurality of layers while unfolding integrally. do.

The electrode assembly for a battery according to the present invention and a method of manufacturing the same are used to produce a cathode having a high probability of occurrence of separation by cutting such as slitting, shearing, notching, etc. Minimize the number of times of cutting by folding the negative electrode plate seamlessly to minimize the cutting surface of the negative electrode can minimize the occurrence of separation generated during cutting.

Due to the minimization of such separation, it is possible to prevent a short short between the positive electrode and the negative electrode, thereby improving the reliability of the battery including the electrode assembly thus manufactured, as well as high output and large capacity.

In addition, the present invention can be eliminated by minimizing the cutting process for the electrode disc with respect to the negative electrode, which eliminates the need for a separate negative electrode cutting equipment, thereby greatly reducing the process time, equipment investment cost and maintenance costs, etc. There is an advantage.

In addition, the present invention can reduce the process time required for the cross-lamination of the positive electrode and the negative electrode in half by folding the single negative electrode plate in various ways with the positive electrode plate and the separator interposed therebetween, thus improving the productivity of the electrode assembly. In addition, the number of production facilities for the electrode assembly can be reduced by half, which can significantly reduce the maintenance cost due to the reduction of facility investment cost and installation space.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention, as used in the singular and the plural unless the context clearly indicates otherwise.

There may be a plurality of embodiments of the present invention, and overlapping descriptions of the same parts as in the prior art may be omitted.

The present invention relates to a battery electrode assembly and a method for manufacturing the battery is manufactured so that the negative electrode is folded in one direction and folded or reciprocating in both directions, and a method of manufacturing the same, between a single negative electrode plate and seamlessly stacked and thus stacked between the negative electrode plate The anode plate and the separator are manufactured so as to be stacked on the cathode, thereby minimizing the separation occurring at the cutting part of the cathode, thereby preventing short circuit between the anode and the cathode, and reducing the manufacturing cost by improving the production speed and simplifying the manufacturing process.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A and 1B are perspective views schematically showing an embodiment of a battery electrode assembly according to the present invention, and FIGS. 2 and 3 are plan views showing one embodiment of a positive electrode and a negative electrode according to the present invention. 5 is a cross-sectional view showing an electrode assembly having a cathode laminated zigzag and folded in multiple layers according to the present invention, and FIG. 5 is a cross-sectional view of an electrode assembly having a cathode laminated in multiple directions and folded in multiple layers according to the present invention. to be.

In order to manufacture the battery electrode assembly 100 according to the present invention, first, an electrode original plate, that is, a positive electrode plate and a negative electrode plate of the positive electrode and the negative electrode is prepared.

In the present invention, the electrode original plate may be supplied while the positive electrode plate 10 or the negative electrode plate 20 having a sufficient length and width is wound on a roll.

In order to form an anode of the electrode assembly, a cathode plate (or unit anode plate) 10 having a predetermined size and shape is formed by using the anode plate, and the size of the electrode assembly 100 to be manufactured by the anode plate 10 is determined. It is formed in an appropriate size so as not to deviate.

In the case of the negative electrode, the negative electrode plate is unfolded from a roll without cutting a predetermined unit, and folded to be alternately stacked with the positive electrode plate 10 with the separator 30 interposed therebetween, and stacked in multiple layers. The negative electrode plate is laminated with the positive electrode plate 10 in a predetermined number according to the electrode assembly 100 and then cut.

Looking at the stacked structure of the negative electrode according to the present invention, a single negative electrode plate 20 and two separators 30 disposed at the upper and lower positions of the negative electrode plate 20 are simultaneously developed, the negative electrode plate 20 and the separator 30 Is folded at an end position of the positive electrode plate 10 and laminated in a plurality of layers with the positive electrode plate 10 interposed therebetween.

As described above, the present invention does not stack a plurality of negative electrode plates, but forms a negative electrode so that the seamless single negative electrode plate 20 is folded and developed to be stacked in a plurality of layers, so that only the front and end portions of the negative electrode plate 20 are cut. Cutting frequency of the negative electrode plate is minimized to minimize the cutting surface of the negative electrode plate 20, thereby minimizing the separation that occurs during cutting.

Further, by excluding the cutting process of the negative electrode negative electrode for the negative electrode, the process time for cutting the negative electrode negatively can be significantly shortened, thereby reducing the facility investment cost and labor costs.

In addition, since the process time required by the cross-lamination of the cathode and the anode can be reduced by half, the productivity of the electrode assembly 100 can be increased, and the number of electrode assembly production equipment can be also reduced by half, thus equipment investment cost and installation of equipment. The cost can be reduced due to the reduction of space.

For example, in the electrode assembly 100 illustrated in FIG. 4, a single cathode plate 20 is reciprocated in both directions, and is stacked in a zigzag form, and one anode plate 10 is formed in each of the stacked layers. ) Is laminated with the separator 30 therebetween.

In addition, referring to FIG. 5 as another embodiment of the present invention, a single negative electrode plate 20 is rolled in one direction and stacked in a plurality of layers, and one positive electrode plate 10 is formed in each of the wound layers to form a separator 30. Laminated in between.

Accordingly, in the present invention, the negative electrode is unfolded and unfolded in one negative electrode plate 20 and is stacked in a plurality of layers, and the edges are exposed except for the front part and the end part while being stacked in a plurality of layers in the electrode assembly 100 of the present invention. Is formed without.

In addition, the separator 30 is folded and stacked in multiple layers while being reciprocally deployed in a zigzag fashion at the same time as the seamless integrated negative electrode plate 20 as shown in FIG. 4, or wound in a predetermined direction simultaneously with the negative electrode plate 20 as shown in FIG. 5. And may be folded and stacked.

In order for the separator 30 to be folded simultaneously with the negative electrode plate 20 to be stacked between the negative electrode plate 20 and the positive electrode plate 10, the negative electrode plate 20 is disposed between the two separators 31 and 32 as described above. Folding expansion can be interposed.

In addition, in order to prevent the cutting portions of the negative electrode plate 20 and the positive electrode plate 10 from being exposed, as shown in FIG. 4, at least a portion of the separation membrane 31 that is developed at a position outside the negative electrode plate 20 of the separator 30 is formed. The electrode assembly 100 is wound while the cut portions of the negative electrode plate 20 and the positive electrode plate 10 are not exposed.

The stacked separator 30 is cut and then cut into a plurality of layers of a single negative electrode plate 20 and a plurality of positive electrode plates 10, and the front and end portions of the separator 30 are stacked in a plurality of the electrode assembly 100 of the present invention. Otherwise it is formed without exposing the edges.

Alternatively, as another embodiment of the present invention, the separator 30 (or unit separator) cut to have a predetermined size and shape is formed, and the negative electrode plate 20 and the positive electrode plate 10 alternately stacked according to the present invention. The separator 30 may be stacked in between to form the electrode assembly 100.

The cut end of the negative electrode plate 20 may be fixed to the outside of the electrode assembly 100 by using an adhesive or by taping, heat fusion and ultrasonic method.

Meanwhile, the electrode disc may be cut by a cutting method such as slitting, shearing, notching, or the like by cutting with scissors, and may be removed according to a preset electrode pattern. The edge portion of the positive electrode plate 10 or the negative electrode plate 20 may be removed using a cutting member having a shape corresponding to the edge portion.

One side or both edge portions of the electrode original plate may be composed of an uncoated portion to which the active material is not applied.

In addition, the non-coated portion may be cut into a predetermined shape (for example, notching) and configured in various shapes.

A positive electrode tab junction 11 is formed at one side or both sides of the positive electrode. For example, as shown in FIGS. 1A to 2, a plain part is cut at one edge of the positive electrode plate 10 to protrude outward from one side of the positive electrode. The positive electrode tab junction 11 can be formed.

The positive electrode tab junction 11 is preferably made of an uncoated portion to which the positive electrode tab 13 is smoothly bonded to the electrode by positive electrode tab bonding (for example, welding), and has various shapes. Of course, it can be formed in a variety of positions.

In this embodiment, the positive electrode includes a current collector formed of a conductive material and an active material coated on at least one surface of the current collector.

In the electrode assembly 100 according to the present invention, the positive electrode has a plurality of stacked numbers, and a separate electrode plate, that is, a positive electrode plate 10 is laminated for each layer, and for this purpose, the positive electrode plate 10 is to be manufactured. The amount corresponding to the number of stacking of the electrode assembly 100 should be prepared.

And, for example, the current collector of the positive electrode may be made of aluminum and the active material may be made of a lithium-based transition metal oxide, but the present invention is not limited to this, the current collector and the active material of the positive electrode is formed of a material other than the material It is also possible that this also falls within the scope of the present invention.

In addition, a positive electrode tab junction 11 protruding outward is formed at one side of the positive electrode.

In the negative electrode composed of the negative electrode plate 20 as shown in FIG. 3, the electrode plates of all the layers are unfolded integrally at the folding portion of the negative electrode plate 20 when manufacturing the electrode assembly 100 according to the present invention, and one electrode for each layer. The plate, that is, is formed to be folded to face the anode formed of the anode plate 10.

Therefore, the length of the electrode plate 20 of the cathode should be provided with a length sufficient to oppose all the anode plates 10 to be laminated.

In this embodiment, in the case of such a negative electrode, the current collector may be formed of copper and the active material may be made of a carbon-based material, but the present invention is not limited thereto, and the current collector and the active material of the negative electrode may be made of a material other than the material. It is also possible that this is also within the scope of the present invention.

Like the positive electrode, the negative electrode tab junction 21 is formed on one side to protrude outward.

As shown in FIG. 1A, the positive electrode tab junction 11 and the negative electrode tab junction 21 are positioned in the same direction, ie, in one direction, and are disposed in different opposite directions as shown in FIG. 1B. Even when the plates 10 and 20 have narrow edges, it is possible to allow the electrode tab junctions 11 and 21 to be positioned.

6A and 6B are perspective views illustrating an embodiment of a lithium secondary battery including the battery electrode assembly 100 according to the present invention.

As shown in FIGS. 6A and 6B, a lithium secondary battery includes an electrode in which a separator 30 is stacked between a first electrode (cathode electrode, hereinafter referred to as an anode) and a second electrode (anode electrode, hereinafter referred to as a cathode). A first electrode tab (hereinafter referred to as a positive electrode tab) 13 and a second electrode tab (hereinafter referred to as a negative electrode tab) 23 respectively connected to the group, the positive electrode and the negative electrode, and the positive electrode tab 13 and the negative electrode Exposing the end of the tab 23, the electrode group and the exterior member 40 for receiving the positive electrode tab 13 and the negative electrode tab 23 therein.

6A and 6B, the electrode group may be configured as an electrode assembly 100 according to the present invention and included in a lithium secondary battery.

In addition, in the lithium secondary battery including the electrode assembly 100 according to the present invention, the electrode tab bonding portions (uncoated portions) 11 and 21 formed at the edges of the electrode plates 10 and 20 to be stacked are illustrated in FIGS. As shown in FIG. 6B, the electrode tabs 13 and 23 are bonded to one side such as the upper end of the electrode tab junctions 11 and 21.

As described above, the positive electrode tab junction 11 and the negative electrode tab junction 21 are positioned in the same direction, ie, in one direction, as well as in different opposite directions as shown in FIG. When the electrode tabs 10 and 20 have narrow edges, the electrode tab junctions 11 and 21 may be positioned even when the edges 20 and 20 have narrow edges. Thus, the electrode tabs 13 and 23 may be provided. do.

In such a lithium secondary battery, a liquid electrolyte may be charged into the exterior material 40 depending on the type of battery, or the separator 30 may serve as an electrolyte. Alternatively, the electrolyte in the liquid state may be filled into the exterior material 40, and then a polymerizable component may be added to finally form the polymer electrolyte.

In addition, in the present embodiment, the exterior member 40 having one side is formed in a pouch shape in which the exterior member 40 is bonded and closed by the adhesive part 41, but the lithium secondary battery according to the present invention is not limited thereto. 40) may consist of a rectangular case of metal or plastic, which is also within the scope of the present invention.

As described above, in the present invention, a plurality of positive electrode plates 10 and a single negative electrode plate 20 are stacked in a plurality of layers with a separator 30 interposed therebetween, and the negative electrode plate 20 is reciprocated to the left and right sides, and is folded. Z-folded electrode assembly 101 of a zigzag shape can be configured, or a single negative electrode plate 20 is wound and wound in one direction, and a plurality of positive electrode plates 10 are sandwiched with a separator 30 therebetween. It is also possible to configure the wound electrode assembly 102 which is stacked one by one.

In the above, the present invention has been described and illustrated by taking the Z-folding type and the winding type electrode assembly 100 as an example, but the present invention is not limited thereto.

In addition, in the present invention, the protruding directions of the positive electrode tab 13 and the negative electrode tag 23 may be arranged in the same direction as shown in FIGS. 1A and 6A, or may be arranged in different directions as shown in FIGS. 1B and 6B. And all are included in the scope of the present invention.

While the invention has been shown and described with respect to certain preferred embodiments thereof, the invention is not limited to these embodiments, and has been claimed by those of ordinary skill in the art to which the invention pertains. It includes all the various forms of embodiments that can be carried out without departing from the spirit.

1A and 1B are perspective views schematically showing an embodiment of a battery electrode assembly according to the present invention.

2 and 3 are plan views showing one embodiment of a positive electrode and a negative electrode according to the present invention

4 is a cross-sectional view showing an electrode assembly having a cathode laminated in multiple layers and reciprocating in zigzag according to the present invention.

5 is a cross-sectional view showing an electrode assembly having a cathode wound in one direction and laminated in multiple layers according to the present invention.

6A and 6B are perspective views illustrating an embodiment of a lithium secondary battery including the battery electrode assembly 100 according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: electrode assembly

10: positive electrode plate 11: positive electrode tab junction

13: anode tab

20: negative electrode plate 21: negative electrode tab junction

23: negative electrode tab

30,31,32: separator

40: exterior material

41: adhesive part

Claims (13)

A single negative electrode plate that is folded and stacked in a plurality of layers while unfolding as a single body; A positive electrode plate laminated between each layer of the negative electrode plate laminated in a plurality of layers; A separator disposed between the cathode plate and the anode plate; A battery electrode assembly, characterized in that comprising a. The method according to claim 1, The negative electrode plate is reciprocated to the left and right, the electrode assembly for a battery, characterized in that stacked in a zigzag form. The method according to claim 1, The negative electrode plate is wound in one direction, the electrode electrode assembly for a battery, characterized in that stacked in a winding type. The method according to claim 1, The electrode assembly for a battery, characterized in that the separator is unfolded integrally unfolded and stacked in a plurality of layers. The method according to claim 4, The electrode assembly for a battery, characterized in that the separator is reciprocated to the left and right to be stacked in a zigzag form. The method according to claim 4, The electrode assembly for a battery, characterized in that the separator is wound in one direction and unfolded and stacked in a winding type. In the lithium secondary battery comprising the electrode assembly of any one of claims 1 to 6, And an exterior member accommodating the electrode tab and the electrode tab while exposing an end portion of the electrode tab, the electrode tab being connected to each electrode of the electrode assembly. A method of manufacturing an electrode assembly for a battery, characterized in that the negative electrode plate and the positive electrode plate are alternately laminated with a separator interposed therebetween, and the negative electrode plate is folded and folded in a plurality of layers while unfolding integrally. The method according to claim 8, A method of manufacturing an electrode assembly for a battery, wherein the negative electrode plate is reciprocated to the left and right to be stacked in a zigzag form. The method according to claim 8, The method of manufacturing an electrode assembly for a battery, characterized in that the negative electrode plate is rolled up in one direction to be unfolded and laminated in a winding type. The method according to claim 8, A method of manufacturing an electrode assembly for a battery, characterized in that the separator is folded while unfolding integrally and laminated in a plurality of layers. The method of claim 11, The method of manufacturing an electrode assembly for a battery, characterized in that the separator is reciprocated to the left and right to be laminated in a zigzag form. The method of claim 11, A method of manufacturing an electrode assembly for a battery, wherein the separator is rolled up in one direction and developed to be wound.

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