阅读说明：本技术 电极组件 (Electrode assembly ) 是由 李信和 李宇镕 成耆殷 于 2019-07-09 设计创作，主要内容包括：根据本发明的一种电极组件,其中,正极和负极交替层叠,并且在所述正极和所述负极之间布置有隔膜,所述电极组件包括：折叠单元,在该折叠单元中负极单元和正极单元交替插入在隔膜的各层之间,所述隔膜的一侧和另一侧在与所述正极和所述负极层叠的方向垂直的方向上以之字形交替折叠；以及层叠单元,在该层叠单元中均切割成预定尺寸的所述正极、所述隔膜和所述负极顺序地层叠,其中,所述负极布置在所述负极单元的最外层,并且所述正极布置在所述正极单元的最外层,并且所述层叠单元层叠在所述折叠单元的最上层和最下层中的每一者上。根据具有上述构造的本发明,具有Z形折叠结构的折叠单元和具有层压和层叠结构的层叠单元可以彼此结合。因此,在折叠单元中,正极相对于负极可以增加面积以增大容量,并且层叠单元可以布置在折叠单元的最外层上以提高稳定性。(An electrode assembly according to the present invention, in which positive electrodes and negative electrodes are alternately laminated with separators disposed therebetween, includes: a folding unit in which a negative electrode unit and a positive electrode unit are alternately inserted between layers of a separator, one side and the other side of the separator being alternately folded in a zigzag shape in a direction perpendicular to a direction in which the positive electrode and the negative electrode are stacked; and a lamination unit in which the positive electrode, the separator, and the negative electrode, each cut to a predetermined size, are sequentially laminated, wherein the negative electrode is disposed at an outermost layer of the negative electrode unit, and the positive electrode is disposed at an outermost layer of the positive electrode unit, and the lamination unit is laminated on each of an uppermost layer and a lowermost layer of the folded unit. According to the present invention having the above-described configuration, the folding unit having the Z-folding structure and the laminating unit having the laminating and laminating structure can be combined with each other. Therefore, in the folded unit, the positive electrode may increase in area relative to the negative electrode to increase capacity, and the stacked unit may be disposed on the outermost layer of the folded unit to improve stability.)

1. An electrode assembly in which positive electrodes and negative electrodes are alternately stacked with separators disposed therebetween, the electrode assembly comprising:

a folding unit in which a negative electrode unit and a positive electrode unit are alternately inserted between layers of a separator, one side and the other side of the separator being alternately folded in a zigzag shape in a direction perpendicular to a direction in which a positive electrode and a negative electrode are stacked; and

a lamination unit in which a cathode, a separator, and an anode each cut to a predetermined size are sequentially laminated,

wherein a negative electrode is disposed at an outermost layer of the negative electrode unit, and a positive electrode is disposed at an outermost layer of the positive electrode unit, and

the stacking unit is stacked on each of the uppermost layer and the lowermost layer of the folding unit.

2. The electrode assembly according to claim 1, wherein the positive electrode, the separator, and the negative electrode stacked in the stacking unit are bonded to each other at contact surfaces therebetween.

3. The electrode assembly according to claim 2, wherein the positive electrode, the separator, and the negative electrode stacked in the stacking unit are bonded to each other by applying heat and pressure.

4. The electrode assembly according to claim 2, wherein, when the laminated unit is laminated on the folded unit, the positive electrode or the negative electrode disposed at the outermost layer of the laminated unit is a one-sided electrode in which an active material is applied to only one surface of a current collector.

5. The electrode assembly according to claim 4, wherein in the one-sided electrode, the active material is applied to a surface in contact with a separator.

6. The electrode assembly according to any one of claims 1 to 5, wherein the negative electrode unit is a negative electrode, and the positive electrode unit is a positive electrode.

7. The electrode assembly according to claim 6, wherein a negative electrode or a positive electrode is laminated on an outermost layer of the folded unit, and

a separator is laminated on a layer of the lamination unit that is in contact with the folding unit.

8. The electrode assembly according to claim 7, wherein the stacking unit is a single cell in which one positive electrode, one negative electrode, and two separators are stacked,

wherein one of the separators is stacked between the positive electrode and the negative electrode, and the other is stacked at a position in contact with an outermost layer of the folded unit.

9. The electrode assembly according to claim 6, wherein a separator is laminated on an outermost layer of the folded unit, and

the laminated unit is a single cell in which one positive electrode, one negative electrode, and one separator are laminated, wherein the separator is laminated between the positive electrode and the negative electrode.

10. The electrode assembly according to claim 6, wherein a negative electrode or a positive electrode is laminated at one of outermost layers of the folded unit, and a separator is laminated at the other outermost layer of the outermost layers,

the laminated unit laminated on one outermost layer on which a positive electrode or a negative electrode is laminated is a single cell in which one positive electrode, one negative electrode, and two separators are laminated, wherein one of the separators is laminated between the positive electrode and the negative electrode, and the other is laminated at a position in contact with the outermost layer of the folded unit, and

the laminated unit laminated on one of the outermost layers of the laminated separator is a single cell in which one positive electrode, one negative electrode, and one separator are laminated, wherein the separator is laminated between the positive electrode and the negative electrode.

11. The electrode assembly according to claim 6, wherein a thickness of the separator laminated between the negative electrode unit and the positive electrode unit in the folded unit is different from a thickness of the separator laminated within the laminated unit.

12. The electrode assembly according to any one of claims 1 to 5, wherein the negative electrode unit is a dual cell in which a negative electrode is laminated at each of two outermost layers and one or more positive electrodes are laminated between the negative electrodes, and

the positive electrode unit is a dual cell in which a positive electrode is laminated at each of two outermost layers, and one or more negative electrodes are laminated between the positive electrodes.

13. The electrode assembly according to claim 12, wherein the negative electrode unit is a double cell in which a negative electrode, a separator, a positive electrode, a separator, and a negative electrode are sequentially stacked from the outermost layer, and

the positive electrode unit is a double-cell in which a positive electrode, a diaphragm, a negative electrode, a diaphragm and a positive electrode are sequentially stacked from the outermost layer.

14. The electrode assembly according to claim 13, wherein the positive electrode, the separator, and the negative electrode, which are stacked to constitute each of the negative electrode unit and the positive electrode unit, are bonded to each other at contact surfaces therebetween.

15. The electrode assembly according to claim 12, wherein a thickness of the separator between the negative electrode unit and the positive electrode unit stacked in the folded unit is different from a thickness of the separator stacked in the negative electrode unit and the positive electrode unit.

16. The electrode assembly according to any one of claims 1 to 3, wherein in the lamination unit, a separator is laminated at an outermost layer at a side opposite to a direction in which the lamination unit faces the folding unit.

17. The electrode assembly according to any one of claims 1 to 3, wherein an auxiliary cell in which a positive electrode, a separator, and a negative electrode each cut to a predetermined size are sequentially stacked is additionally stacked on an outer surface of the stacking unit.

18. The electrode assembly of claim 17, wherein the auxiliary cell has the same lamination structure as the lamination unit.

19. The electrode assembly according to any one of claims 1 to 3, wherein two or more folded units are successively laminated between the laminated units arranged at the uppermost layer and the lowermost layer.

20. The electrode assembly according to claim 19, wherein the lamination unit in which the positive electrode, the separator, and the negative electrode, each cut to a predetermined size, are sequentially laminated, is interposed between the two folding units that are continuously laminated.

21. The electrode assembly according to any one of claims 1 to 3, wherein the negative electrode unit laminated on the folded unit is a negative electrode, and the positive electrode unit is a positive electrode,

the area of the negative electrode is larger than that of the positive electrode, and

the gap (d) between the folding point of the separator and the negative electrode is smaller than the gap between the folding point of the separator and the positive electrode.

22. The electrode assembly according to any one of claims 1 to 3, wherein in the folding unit, the end of the separator includes an extension extending a predetermined length, and

the extension part surrounds the folding unit and the stacking unit after the stacking unit is stacked on the upper and lower parts of the folding unit, and the end of the extension part is bonded to be fixed to the surface of the folding unit or the stacking unit.

23. A secondary battery in which the electrode assembly according to any one of claims 1 to 5 is embedded in a pouch.

24. A secondary battery module mounted such that a plurality of secondary batteries according to claim 23 are mounted to be electrically connected to each other.

Technical Field

The present invention relates to an electrode assembly embedded in a secondary battery, and more particularly, to an electrode assembly having advantages of a relatively stable structure of a lamination and lamination method and relatively small allowable tolerance of a Z-folding method.

Background

Unlike the primary battery, the secondary battery is rechargeable, and the possibility of compact size and high capacity is high. Therefore, recently, many studies have been made on rechargeable batteries. As technology develops and the demand for mobile devices increases, the demand for rechargeable batteries as an energy source is rapidly increasing.

Such a secondary battery is configured such that an electrode assembly is built in a battery case (e.g., pouch, can, etc.). Due to such a structure in which the positive electrode, the separator, and the negative electrode are stacked, the electrode assembly built in the battery case can be repeatedly charged and discharged.

Fig. 1a is a side view illustrating a process of manufacturing a unit cell 4 to be laminated in an electrode assembly through a lamination and lamination process among electrode assemblies according to the related art, and fig. 1b is a side view illustrating a laminated state of a plurality of unit cells 4 manufactured in fig. 1 a.

Referring to the drawings, the cathode 1, the separator 3, the anode 2, and the separator 3 in a state of being wound in the form of a roll are continuously unwound in a laminated and laminated manner. Here, each of the cathode 1 and the anode 2 is cut into a predetermined size and moved together with the continuously supplied separator 3 to pass through the lamination device. Here, the cathode 1 has a structure in which a cathode active material is applied to the surface of a cathode current collector, and the anode 2 has a structure in which an anode active material is applied to the surface of an anode current collector.

While passing through the lamination apparatus, heat and pressure may be applied between the cathode 1, the separator 3, the anode 2, and the separator 3 to bond the cathode 1, the separator 3, the anode 2, and the separator 3 to each other. In the joined state, the positive electrode 1 and the positive electrode 1 adjacent to each other (the negative electrode 2 and the negative electrode 2 adjacent to each other) are cut off therebetween, thereby continuously manufacturing one unit cell 4 in which the positive electrode 1, the separator 3, the negative electrode 2, and the separator 3 are sequentially laminated downward. The unit cells 4 are stacked in a predetermined number to manufacture an electrode assembly.

Further, the electrode assembly according to the related art may also be manufactured by a Z-folding method. The electrode assembly manufactured by the Z-folding method has a structure in which a continuously supplied separator is disposed at the center while positive and negative electrodes are alternately inserted at both sides, and then folded in a zigzag shape. It is known from Korean patent laid-open Nos. 10-2014-0062761, 10-2011-0048839, etc.

In the lamination and lamination method as described above, since the layers to be laminated are bonded to each other, the electrode assembly may have excellent durability against external impact and be stable as compared to other manufacturing methods. On the other hand, since the processes are performed in the order of lamination of the electrodes and the separators, lamination, cutting, and lamination of the unit cells, the number of processes is greater than that of other processes. On the other hand, in the case of the Z-folding method, the processing time is shorter as compared with the laminating and laminating method, thereby achieving higher productivity.

Further, as the number of processes increases, the allowable tolerance of each process may accumulate. For example, in the lamination and lamination method, the allowable tolerance is determined in consideration of the allowable tolerance when cutting the positive electrode and the negative electrode in the case of laminating the electrode and the separator and the allowable tolerance when cutting into unit cells. As a result, the allowable tolerance in the electrode assembly manufactured by the lamination and lamination method can be reduced. Therefore, there is a problem that the size of the positive electrode relative to the negative electrode increases. On the other hand, when the electrode assembly is manufactured in a Z-folding manner, the size of the positive electrode may be larger than that of the negative electrode because the number of processes is small.

That is, since the capacity of the electrode assembly increases due to the size of the positive electrode being larger than that of the negative electrode, the size of the positive electrode is preferably increased as much as possible. However, the size of the positive electrode is limited within a certain range to reduce the deterioration of the positive electrode and the possibility of occurrence of short circuits. Here, the size of the positive electrode is further reduced due to an allowable tolerance during production, but since the number of processes is increased (due to a large allowable tolerance), the manner of lamination and lamination further limits the size of the positive electrode.

Disclosure of Invention

Technical problem

Accordingly, it is a primary object of the present invention to provide an electrode assembly having advantages of an electrode assembly using a Z-folding method (the size of a positive electrode is increased compared to a negative electrode due to reduction of allowable tolerances) and advantages of an electrode assembly using a lamination and lamination method (a negative electrode, a separator, and a positive electrode constituting a unit cell are combined to improve stability).

Technical solution

The present invention for achieving the above object includes an electrode assembly in which positive electrodes and negative electrodes are alternately stacked with a separator disposed therebetween, the electrode assembly including: a folding unit in which negative electrode units and positive electrode units are alternately interposed between the layers of the separator, one side and the other side of the separator being alternately folded in a zigzag shape in a direction perpendicular to a direction in which the positive and negative electrodes are stacked; and a lamination unit in which a cathode, a separator, and an anode, each cut to a predetermined size, are sequentially laminated, wherein the anode is disposed at an outermost layer of the anode unit, and the cathode is disposed at an outermost layer of the cathode unit, and the lamination unit is laminated on each of an uppermost layer and a lowermost layer of the folded unit.

Further, the positive electrode, the separator, and the negative electrode stacked in the stacking unit may be bonded to each other at a contact surface therebetween. The bonding in the laminated unit may be performed by applying heat and pressure.

When the laminated unit is laminated on the folded unit, the positive electrode or the negative electrode disposed at the outermost layer of the laminated unit may be a single-sided electrode in which an active material is applied to only one surface of a current collector.

Here, in the single-sided electrode, the active material may be applied to a surface in contact with the separator. That is, the positive electrode collector or the negative electrode collector may be disposed at the outermost layer.

In the first embodiment of the present invention, the negative electrode unit may be a negative electrode, and the positive electrode unit may be a positive electrode. Further, a negative electrode or a positive electrode may be stacked on the outermost layer of the folded unit, and a separator may be stacked on a layer of the stacked unit that is in contact with the folded unit.

In this embodiment, the lamination unit may be a single cell in which one positive electrode, one negative electrode, and two separators are laminated, wherein one of the separators may be laminated between the positive electrode and the negative electrode, and the other may be laminated at a position in contact with the outermost layer of the folded unit.

In the second embodiment, a separator may be stacked on an outermost layer of the folded unit, and the stacked unit may be a single cell in which one positive electrode, one negative electrode, and one separator are stacked, wherein the separator may be stacked between the positive electrode and the negative electrode.

In the third embodiment, a negative electrode or a positive electrode may be stacked at one outermost layer of the folded unit, and the separator may be laminated at the other outermost layer among the outermost layers, the laminated unit laminated on the outermost layer on which the positive electrode or the negative electrode is laminated may be a single cell in which one positive electrode, one negative electrode, and two separators are laminated, wherein one of the separators is stacked between the cathode and the anode, and the other of the separators may be stacked at a position in contact with the outermost layer of the folded unit, and the laminated unit laminated on one of the outermost layers on which the separator is laminated may be a single electric core, in the single cell, a positive electrode, a negative electrode, and a separator are stacked, wherein the separator may be stacked between the positive electrode and the negative electrode.

In the foregoing embodiment, the thickness of the separator laminated between the negative electrode unit and the positive electrode unit in the folded unit may be different from the thickness of the separator laminated within the laminated unit.

Further, the negative electrode unit may be a bicore in which a negative electrode is laminated at each of two outermost layers and one or more positive electrodes are laminated between the negative electrodes, and the positive electrode unit may be a bicore in which a positive electrode is laminated at each of two outermost layers and one or more negative electrodes are laminated between the positive electrodes. In more detail, the negative electrode unit may be a dual cell in which a negative electrode, a separator, a positive electrode, a separator, and a negative electrode are sequentially stacked from an outermost layer, and the positive electrode unit may be a dual cell in which a positive electrode, a separator, a negative electrode, a separator, and a positive electrode are sequentially stacked from an outermost layer. Here, the cathode, the separator, and the anode, which are stacked to constitute each of the anode unit and the cathode unit, may be bonded to each other at a contact surface therebetween.

Further, the thickness of the separator between the negative electrode unit and the positive electrode unit stacked in the folded unit may be different from the thickness of the separator stacked in the negative electrode unit and the positive electrode unit.

Further, in the lamination unit, the separator may be laminated at an outermost layer at a side opposite to a direction in which the lamination unit faces the folding unit.

Further, a lamination unit in which a positive electrode, a separator, and a negative electrode each cut to a predetermined size are sequentially laminated may be additionally laminated on an outer surface of the lamination unit. Among the lamination units, the lamination units disposed at the upper and lower portions of the folding unit may have the same lamination structure, and more or less electrodes are laminated according to the specification of the electrode assembly.

Further, two or more folding units may be successively stacked between the stacking units disposed at the uppermost layer and the lowermost layer, as necessary. Here, the lamination unit in which the cathode, the separator, and the anode, each of which is cut to a predetermined size, are sequentially laminated may be interposed between the two folding units that are continuously laminated. The stacked unit 200 may be a dual cell in which the uppermost layer and the lowermost layer have the same polarity, or may be a single cell in which the uppermost layer and the lowermost layer have different polarities from each other, and may have the same structure as the stacked unit disposed at each of the upper and lower portions of the folded unit.

Further, the negative electrode unit stacked on the folded unit may be a negative electrode, and the positive electrode unit may be a positive electrode, the area of the negative electrode may be larger than that of the positive electrode, and the gap (d) between the folded point of the separator and the negative electrode may be smaller than that between the folded point of the separator and the positive electrode.

Further, in the folding unit, an end of the diaphragm may include an extension part extending a predetermined length, and after the stacking unit is stacked at upper and lower portions of the folding unit, the extension part may surround the folding unit and the stacking unit, and an end of the extension part may be bonded to be fixed to a surface of the folding unit or the stacking unit.

Further, since the electrode assembly having the above technical features is provided, the present invention may additionally provide a secondary battery in which the electrode assembly according to the present invention is embedded in a pouch, and a secondary battery module in which a plurality of secondary batteries are electrically connected to each other.

Advantageous effects

According to the present invention having the above-described configuration, a folding unit having a Z-folding structure (a structure having an electrode assembly manufactured in a Z-folding manner) and a stacking unit having a lamination and stacking structure (a structure having an electrode assembly manufactured according to a lamination and stacking method) may be coupled to each other. Therefore, in the folded unit, the positive electrode may increase in area relative to the negative electrode to increase capacity, and the stacked unit may be disposed on the outermost layer of the folded unit to improve stability.

Further, the positive electrode or the negative electrode disposed at the outermost layer of the lamination unit may be provided as a single-sided electrode in which an active material is applied to only one surface of a current collector to reduce deterioration due to precipitation of the active material, and also reduce the possibility of occurrence of a short circuit due to external impact.

Further, the thickness of the separator between the negative electrode unit and the positive electrode unit stacked in the folded unit may be different from the thickness of the separator stacked in the stacked unit to minimize the volume.

The present invention may provide a structure in which the separator is laminated on the outermost layer at the opposite side of the direction in which the laminated unit faces the folding unit; and a structure in which a plurality of stacked units are additionally stacked to provide various structures according to the required specifications of the secondary battery.

Two or more folding units may be stacked in series. That is, when the number of stacks of the folding units increases, the cumulative tolerance may increase. Therefore, two folding units each having a smaller number of laminations can be stacked to reduce the cumulative tolerance, and the number of laminations can be increased to increase the capacity.

In addition, in the folding unit, the end of the diaphragm may include an extension part extending a predetermined length, and after the stacking unit is stacked on the upper and lower parts of the folding unit, the extension part may surround the folding unit and the stacking unit, and the end of the extension part may be bonded to be fixed to a surface of the folding unit or the stacking unit, thereby preventing shaking of the folding unit and the stacking unit and improving durability against external impact.

Further, the present invention may additionally provide a secondary battery in which the electrode assembly according to the present invention is embedded in a pouch, and a secondary battery module in which a plurality of secondary batteries are electrically connected to each other.

Drawings

Fig. 1a is a side view illustrating a state in which unit cells are manufactured in a laminated and layered manner.

Fig. 1b is a front view illustrating a state in which unit cells manufactured in fig. 1a are stacked to manufacture an electrode assembly.

Fig. 2 is a front view illustrating a process of manufacturing an electrode assembly according to a first embodiment of the present invention.

Fig. 3 is a front view illustrating a process of manufacturing an electrode assembly according to a second embodiment of the present invention.

Fig. 4 is a front view illustrating a process of manufacturing an electrode assembly according to a third embodiment of the present invention.

Fig. 5a is a front view illustrating a process of manufacturing an electrode assembly according to a fourth embodiment of the present invention.

Fig. 5b is a front view illustrating a process of manufacturing an electrode assembly derived from the fourth embodiment of the present invention.

Fig. 6 is a front view illustrating a process of manufacturing an electrode assembly according to a fifth embodiment of the present invention.

Fig. 7 is a front view illustrating a process of manufacturing an electrode assembly according to a sixth embodiment of the present invention.

Fig. 8 and 9 are front views illustrating a process of manufacturing an electrode assembly according to a seventh embodiment of the present invention.

Fig. 10 is a front view showing a gap "d" between the folding point of the separator in the folding unit and the negative electrode.

Fig. 11 is a front view illustrating a process of manufacturing an electrode assembly according to an eighth embodiment of the present invention.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out the technical idea of the present invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly illustrate the present invention, portions not related to the present description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In addition, the terms or words used in the present specification and claims should not be construed restrictively as a general meaning or a dictionary-based meaning, but should be construed as a meaning and concept conforming to the scope of the present invention based on the principle that the inventor can appropriately define the concept of the term to describe and explain his invention in the best way.

The present invention relates to an electrode assembly in which positive electrodes 10 and negative electrodes 20 are alternately stacked, and separators 30 and 40 are disposed between the positive electrodes 10 and the negative electrodes 30. The electrode assembly has the following structure: in which the laminated unit 200 manufactured in a lamination and lamination manner is laminated on each of both sides (upper and lower sides) of the folded unit 100 manufactured in a Z-fold manner.

That is, in the folded unit 100, the cathode units and the anode units are alternately inserted between the layers of the separator 40, and one side and the other side of the separator 40 are folded in a zigzag shape in a direction (horizontal direction in fig. 2) perpendicular to a direction (vertical direction in fig. 2) in which the cathodes 10 and 20 are stacked.

Here, a negative electrode unit in which a negative electrode is arranged on each of the outermost layers (the uppermost layer and the lowermost layer) and a positive electrode unit in which a positive electrode is arranged on each of the outermost layers are cells constituting a single electrode or a single unit.

Further, the laminated unit has the following structure: in which a cathode 10, a separator 30, and an anode 20, each cut to a predetermined size, are sequentially laminated. The cathode 10, the separator 30, and the anode 20 stacked in the stacking unit are bonded to each other at contact surfaces therebetween by heat and pressure. The laminated unit has a structure in which one separator 30 is further added when the anode 20 and the cathode 10 are arranged at the outermost layers of the folded unit 100.

Further, when the laminated unit 200 is laminated on each of the upper and lower layers of the folded unit 100, the positive electrode or the negative electrode disposed at the outermost layer of the laminated unit 200 is a one-sided electrode in which an active material is applied to only one surface of a current collector. The one-sided electrode disposed at the outermost layer is disposed such that an active material is applied to a surface in contact with the separator (thereby disposing the positive electrode collector or the negative electrode collector at the outermost layer).

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings.

First embodiment

Fig. 2 is a front view illustrating a process of manufacturing an electrode assembly according to a first embodiment of the present invention. As shown in the drawing, in the folding unit according to the present embodiment, the negative electrode is one single negative electrode 20, and the positive electrode is one single positive electrode 10.

Further, the laminated unit is a single cell in which one positive electrode 10, one negative electrode 20, and two separators 30 are laminated. In the lamination unit, one of the separators 30 is laminated between the positive electrode 10 and the negative electrode 20, and the other is laminated at a position in contact with the positive electrode 10 disposed at the outermost layer of the folded unit 100. That is, in the lamination unit, the positive electrode 10, the separator 30, the negative electrode 20, and the separator 30 are laminated in this order from the outermost layer.

In this embodiment, although the positive electrode 10 is laminated on the outermost layer of the folded unit 100 and the outermost layer of the laminated unit 200, the present invention is not limited thereto. For example, the negative electrode 20 may be laminated on the outermost layer of the folded unit 100 and the outermost layer of the laminated unit 200.

The folded unit 100 has a structure in which n electrodes (the sum of the number of stacked positive and negative electrodes) are stacked, where n is a natural number at least greater than 2. In this embodiment, the stacking unit 200 is stacked on each of the upper and lower layers of the folding unit 100, with the positive electrode 10 disposed at each of the uppermost and lowermost layers. Here, the lamination unit 200 is laminated such that the surface on which the separator is disposed contacts the outermost positive electrode 10 of the folded unit 100.

This embodiment is the embodiment having the most basic laminated structure in the present invention. Therefore, the second to fourth embodiments, which will be described later, may have a structure modified according to the structure of the first embodiment, but have the same technical idea as the first embodiment in that the stacking unit 200 is additionally stacked on both sides of the folding unit 100.

Second embodiment

Fig. 3 is a front view illustrating a process of manufacturing an electrode assembly according to a second embodiment of the present invention. In the present embodiment, the separator 40 is laminated on the outermost layer of the folded unit 100 (unlike the first embodiment, when the positive and negative electrodes are alternately inserted into both sides of the separator of the folded unit, the electrodes are not laminated on the uppermost layer).

In addition, the stacking unit 200 additionally stacked on each of the upper and lower layers of the folding unit 100 is provided as a single cell in which one positive electrode 10, one negative electrode 20, and one separator 300 are stacked.

As shown in the drawing, since the electrode disposed at the outermost layer of the folded unit 100 is the positive electrode 10, the stacked units 200 are stacked in a direction in which the negative electrode 20 faces the folded unit 100.

Third embodiment

Fig. 4 is a front view illustrating a process of manufacturing an electrode assembly according to a third embodiment of the present invention. In this embodiment, the positive electrode 10 is laminated on the uppermost layer of the outermost layers of the folded unit 100, and the separator 40 is disposed on the lowermost layer.

Further, the stacked unit 200 stacked on the upper side of the folded unit 100 has a single cell structure in which the positive electrode 10, the separator 30, the negative electrode 20, and the separator 30 are sequentially stacked from the outermost layer (uppermost layer), similarly to the first embodiment. In addition, similar to the second embodiment, the stacking unit 200 stacked on the lower side of the folding unit 100 is provided as a single cell in which one positive electrode 10, one separator 30, and one negative electrode 20 are stacked. Here, the negative electrode 20 faces upward.

Fourth embodiment

Fig. 5a is a front view illustrating a process of manufacturing an electrode assembly according to a fourth embodiment of the present invention.

In the present embodiment, each of the positive electrode unit and the negative electrode unit is provided as a double cell C (C-type double cell in which a positive electrode is disposed in an intermediate layer) in which a plurality of electrodes are stacked instead of a single electrode. That is, the negative electrode unit is a bicell C in which the negative electrodes 20 are laminated on both outermost layers and one or more positive electrodes 10 are laminated between the negative electrodes 20, and the positive electrode unit is a bicell a (a type bicell in which the negative electrodes are laminated on an intermediate layer) in which the positive electrodes 10 are laminated on both outermost layers and one or more negative electrodes 20 are laminated between the positive electrodes 10.

In more detail, as shown in the drawing, the positive electrode unit is an a-type dual cell in which a positive electrode 10, a separator 30, a negative electrode 20, a separator 30, and a positive electrode 10 are sequentially laminated from the outermost layer, and the negative electrode unit is a C-type dual cell in which a negative electrode 20, a separator 30, a positive electrode 10, a separator 30, and a negative electrode 20 are sequentially laminated from the outermost layer.

Here, the cathode 10, the separator 30, and the anode 20, which are stacked to constitute each of the anode unit and the cathode unit, are bonded to each other at the contact surface therebetween. Each of the negative electrode unit and the positive electrode unit is configured such that three electrodes are stacked, but the present invention is not limited thereto. For example, five, seven, or more electrodes may be stacked.

The folding unit 100 is configured such that the diaphragm 40 is disposed at the uppermost layer and the lowermost layer. In addition, the stacking unit 200 stacked on each of the upper and lower sides of the folding unit 100 is provided as a double cell (more specifically, a-type double cell). That is, in the bicore laminated at the outermost layer of the folded unit 100, the negative electrode 20 is disposed at the outermost layer. Further, the lamination unit 200 has a dual-cell structure in which the positive electrode 10 is disposed on a surface in contact with the folding unit 100. Here, in the lamination unit 200, although three electrodes are laminated in the drawing, the present invention is not limited thereto. For example, five, seven, or more electrodes may be stacked.

Further, fig. 5b shows a state in which an area difference between the separator and the anode is not generated or is small in the electrode assembly according to the fourth embodiment. Referring to the drawings, in the bicore a constituting the negative electrode unit and the bicore a constituting the positive electrode unit shown in fig. 5a, the separator 40 has the widest area, followed by the negative electrode 20 having the widest area and the positive electrode 10 having the smallest area. On the other hand, in the bicore C and the bicore a shown in fig. 5b, the area of the negative electrode 20 is equal to or slightly smaller than the area of the separator 30 (in more detail, the length difference "d" between the negative electrode and the separator shown in fig. 5b corresponds to about 0 to 0.3% of the length of the separator).

As described above, if the area difference between the anode 20 and the separator 30 is not generated or reduced, the area of the anode 20 may be more increased than that of the separator (as shown in fig. 5 a) under the condition that the electrode assembly has the same volume. As a result, the area of the positive electrode 10 can also be increased to increase the charge and discharge capacity. In addition, since the measurement accuracy of the sensor (visual sensor) is improved in the production process (since there is no portion covered with the separator having a length larger than that of the anode), the size and relative position of the anode 20 can be grasped more accurately to reduce production tolerances. When the tolerance is reduced as described above, the size of the negative electrode may increase.

Although the positive electrode unit and the negative electrode unit are provided as the C-type bicells and the a-type bicells in this embodiment, the present invention is not limited thereto. For example, each of the positive electrode and the negative electrode may be provided as a single cell in which the uppermost electrode and the lowermost electrode are different from each other (e.g., a battery in which a positive electrode, a separator, a negative electrode, a separator; a positive electrode, a separator, a negative electrode, a separator, a positive electrode, a separator, a negative electrode; a separator, a positive electrode; a negative electrode; a separator, a positive electrode, a separator, a negative electrode; a separator, a positive electrode, etc. are stacked downward in this order). Further, even if provided as a single cell, for the reasons described above, it is preferable that the difference in area between the separator 30 and the anode 20 should be produced as minimally as possible. That is, the size of the anode may be 99.7% to 100% of the size of the separator.

Although the coupling structure of the folding unit 100 and the stacking unit 200 has been described according to the first to fourth embodiments of the present invention, if the coupling structure has the following structure: wherein the negative electrode unit and the positive electrode unit are inserted into the separator 40 while the separator 40 is folded in a zigzag shape, the structure can be applied to the folded unit 100 of the present invention, and if the coupling structure has the following structure: in which the electrodes 10 and 20 and the separator 30 are sequentially stacked, the structure can be applied to the stacked unit 200 of the present invention. In addition to the foregoing embodiments, further various combinations are possible.

For reference, the electrode assemblies according to the first to fourth embodiments may be manufactured by various applicable manufacturing methods. Here, it is preferable that the stacking unit 200 is stacked on each of the upper and lower layers of the folding unit 100, and then, heat and pressure are applied between the folding unit 100 and the stacking unit 200 to generate a predetermined bonding force. That is, the coupling force between the folding unit 100 and the stacking unit 200 may prevent the folding unit 100 and the stacking unit 200 from being separated from each other when the electrode assembly is embedded in the pouch and external impact is applied to the pouch. When predetermined heat and pressure are applied in the vertical direction (stacking direction) after the folding unit 100 and the stacking unit 200 are completely stacked, such bonding may be generated by heat pressing of the separators.

One of the reasons why the lamination unit 200 is laminated on the outer surface of the folding unit 100 in the present invention is because the one-sided electrode is easily disposed on the outermost layer in the electrode assembly. That is, in order to arrange the one-sided electrode at the outermost layer of the folded unit 100 without additionally stacking the stacked unit 200, means for separately inserting the one-sided electrode is required in addition to means for sequentially inserting the negative electrode unit and the positive electrode unit from the left and right sides. However, the means for separately inserting the single-sided electrode may interfere with the means for inserting the negative electrode unit and the positive electrode unit, and may increase manufacturing time because the single-sided electrode is separately inserted. On the other hand, a structure in which the lamination unit 200 is added to the outer surface of the folding unit 100 (the single-sided electrode is laminated on the outermost layer), similar to the structure according to the present invention, in which the lamination unit 200 and the folding unit 100 are separately manufactured, may have an advantage of simplifying the manufacturing process. Further, since the laminated unit has the following structure: in which a plurality of electrodes and separators are bonded to each other and have a thickness thicker than that of a single-sided electrode, the stacked unit can be stacked more stably and efficiently than a case where only a single-sided electrode is stacked during the manufacturing process. For example, since the thickness of the one-sided electrode is thinner than that of a single positive electrode or negative electrode, the lamination speed may be limited to prevent the electrode from being damaged. However, the stacked unit may have the advantage of being relatively free under constraints.

As described above, when the electrode (positive electrode or negative electrode) laminated on the outermost layer is a one-sided electrode instead of a double-sided electrode, deterioration of the electrode due to precipitation of the active material may be reduced, and the possibility of occurrence of a short circuit due to external impact may be reduced.

Therefore, in the present invention, the electrode (positive electrode in fig. 5) disposed at the outermost layer of the laminated unit 200 is provided as a single-sided electrode. That is, as shown in fig. 5, the positive electrode disposed at the outermost layer of the lamination unit 200 is provided as a single-sided electrode in which only the surface of the positive electrode collector 11 facing the separator 30 is applied with the positive electrode active material 12, and the surface exposed to the outside is not applied with the positive electrode active material 12.

As described above, such a structure in which the one-side electrode is disposed at the outermost layer of the stacked unit 200 can be applied to the first to third embodiments in addition to the fourth embodiment.

Further, in the present invention, the thickness of the separator 40 stacked between the negative electrode unit and the positive electrode unit in the folded unit is different from the thickness of the separator 30 stacked within the stacked unit 200 and the thickness of the separator 30 stacked within the double cell in the case where each of the negative electrode unit and the positive electrode unit is provided as the double cell. That is, because the diaphragm 40 is subjected to an external force during folding in the manufacturing process, the diaphragm 40 may have a thicker thickness or be made of a material having higher durability.

In the present invention, since the electrode assembly having the above technical features is provided, it is possible to additionally provide a secondary battery in which the electrode assembly having the above structure is embedded in a pouch and a secondary battery module in which a plurality of secondary batteries are mounted to be electrically connected to each other.

In the present invention having the above structure, since the folding unit 100 having the Z-shaped folding structure and the stacking unit 200 having the laminating and stacking structure are coupled to each other, the size of the positive electrode can be increased to increase the capacity with respect to the negative electrode in the folding unit 100 (i.e., since the allowable tolerance according to the production process, which is one factor that the size of the positive electrode must be reduced in a state where the negative electrode has a fixed size, is minimized as described above, the size of the positive electrode is set to the maximum value in consideration of the allowable tolerance), and since the stacking unit 200 in which the separator and the electrode disposed at the outermost layer of the folding unit 100 are combined with each other is provided, thereby improving the stability, that is, the effect of the increase in the size of the positive electrode with respect to the negative electrode due to the reduction in the allowable tolerance can be simultaneously achieved; and an effect of stability increase, wherein the effect of stability increase is an advantage of a lamination and lamination type electrode assembly, and the effect of size increase of the positive electrode with respect to the negative electrode is an advantage of a Z-folding type electrode assembly.

Further, the cathode 10 or the anode 20 disposed at the outermost layer of the lamination unit 200 may be provided as a single-sided electrode in which an active material is applied to only one surface of a current collector to reduce deterioration and also reduce the possibility of occurrence of a short circuit due to external impact.

The present invention can be easily applied to an electrode assembly having a Z-folded structure according to the related art by adding only the stacking unit 200, and can provide a structure in which a single-sided electrode is easily disposed at the outermost layer.

In addition, the thickness of the separator 40 stacked between the negative electrode unit and the positive electrode unit in the folded unit 100 and the thickness of the separator 40 stacked within the stacked unit may be different from each other to minimize the volume of the electrode assembly.

Further, in the present invention, the structures according to the fifth to eighth embodiments are additionally provided as structures suitable for the electrode assemblies according to the first to fourth embodiments.

Fifth embodiment

Fig. 6 is a front view illustrating a process of manufacturing an electrode assembly according to a fifth embodiment of the present invention.

This embodiment is characterized in that a separator is additionally laminated on the outermost layers (the uppermost layer and the lowermost layer) of the electrode assembly according to the previous embodiment.

That is, in the electrode assemblies according to the first to fourth embodiments, when the electrodes 10 and 20 are disposed at the outermost layers and then inserted into the pouch, the electrodes 10 and 20 may directly contact the inner wall of the pouch.

Generally, the bag is made of a material including a metal component (aluminum or the like), although the material is changed according to the type of the bag. Accordingly, the separator laminated at the outermost layer may protect the electrode assembly from chemical changes or external impacts when the electrode assembly is inserted into the pouch.

Sixth embodiment

Fig. 7 is a front view illustrating a process of manufacturing an electrode assembly according to a sixth embodiment of the present invention.

This embodiment has a structure in which auxiliary cells, in which the positive electrode 10, the separator 30, and the negative electrode 20, each of which is cut to a predetermined size, are sequentially stacked, are additionally stacked at the outermost layers (the uppermost layer and the lowermost layer) of each electrode assembly according to the foregoing embodiment.

The auxiliary cell may have the following structure: wherein the separator, the negative electrode, and the separator are bonded to each other. Alternatively, as shown in fig. 7, the auxiliary cell may have the same structure as the lamination unit 200, that is, a structure in which a cathode, a separator, an anode, and a separator are combined with each other. In addition, more or less electrodes and a structure in which a separator is laminated may be provided according to the specification of the electrode assembly.

Seventh embodiment

Fig. 8 and 9 are front views illustrating a process of manufacturing an electrode assembly according to a seventh embodiment of the present invention.

In this embodiment, two or more folding units 100 are sequentially stacked between the stacking units 200 disposed at the uppermost layer and the lowermost layer of the electrode assembly according to the previous embodiment.

In the Z-fold manner, the cumulative tolerance may increase as the number of layers stacked increases. Therefore, even if the folding units 100 have the same number of stacks, the cumulative tolerance can be reduced in the following structure: in which two folding units having the same number of stacks are separately manufactured and then combined with each other, instead of manufacturing one stacking unit having a greater number of stacks. Therefore, in the structure according to the present embodiment, two folding units each having a smaller number of laminations can be stacked to reduce the cumulative tolerance, and the number of laminations can also be increased to increase the capacity.

Here, one or more lamination units 200 (see fig. 9) are additionally interposed between two folding units 100 that are successively laminated, each lamination unit 200 having a structure in which a cathode, a separator, and an anode, each of which is cut to a predetermined size, are sequentially laminated. Each of the stacking units 200 may have dual cells in which the uppermost layer and the lowermost layer have the same polarity or single cells in which the uppermost layer and the lowermost layer have different polarities from each other according to the polarity of the outermost electrode of the folding unit 100. Alternatively, the stacking unit 200 may have a structure in which dual cells and single cells are combined with each other or a structure in which a plurality of specific single cells or dual cells are combined with each other and stacked.

In some cases, the structure of the stacking unit 200 stacked between two folding units 100 and the structure of the stacking unit 200 stacked at upper and lower layers of the folding units 100 may be identical.

Preferably, the anode 20 and the cathode 10 are manufactured such that the gap d between each of the anode 20 and the cathode 10 and the folding point of the separator 40 becomes zero or close to zero as much as possible to reduce the accumulated tolerance and prevent the separator 40 from sagging or wrinkling.

That is, referring to fig. 10 showing the gap d between the folding point of the separator 40 and the negative electrode, the negative electrode unit stacked in the folding unit 100 is one negative electrode 20, and the positive electrode unit stacked in the folding unit 100 is one positive electrode 10. In this drawing, the gap d between the folding point of the separator 40 and the anode is larger than zero due to the thickness of the anode 20. However, since each of the anode 20 and the separator 40 actually has a sufficiently thin thickness, and the separator 40 has elasticity, the gap d between the folding point and the anode 20 may be zero or close to zero (the end side of the anode 20 is arranged in contact with the folding point of the separator).

Here, since the gap d generated in the anode 20 becomes zero, the anode 20 may have the maximum area when the electrode assembly has the same volume. As the area of the negative electrode 20 increases (the area of the positive electrode is smaller than that of the negative electrode and must be reduced due to tolerance), the area of the positive electrode 10 also increases. Therefore, as the gap d generated in the anode 20 approaches zero, the area of the cathode 10 increases to increase the capacity. As a result, it is preferable that the folding unit according to the present invention is manufactured such that the gap d between the folding point of the separator and the anode 20 is zero or close to zero.

Eighth embodiment

Fig. 11 is a front view illustrating a process of manufacturing an electrode assembly according to an eighth embodiment of the present invention.

This embodiment is characterized in that one end of the diaphragm 40 in the folding unit 200 has an extension 41 extending a predetermined length.

As shown in the drawings, after the stacking units 100 are stacked on the upper and lower portions of the folding unit 100, respectively, the extension 41 may surround the folding unit 100 and the stacking unit 200, and the end of the extension 41 may be bonded to be fixed to the surface of the folding unit 100 or the stacking unit 200.

Fig. 6 to 11 show only states in which the features according to the sixth to eighth embodiments are applied to the electrode assembly according to the first embodiment. However, the features according to the sixth to eighth embodiments may be applied to the electrode assemblies according to the second to fourth embodiments in addition to the electrode assembly of the first embodiment.

The present invention can provide: a structure in which the separator 30 is laminated on the outermost layer at the opposite side of the direction in which the laminated unit 200 faces the folding unit 100; and a structure in which an auxiliary cell is additionally stacked on the outer surface of the stacking unit 200. That is, the present invention can provide various structures according to the specifications of a desired secondary battery.

Two or more folding units 100 may be successively stacked to reduce the accumulated tolerance, and the number of stacks may be increased to increase the capacity.

In addition, in the folding unit 100, one end of the diaphragm 40 may have an extension 41 extending a predetermined length. In addition, the extension 41 may surround the folding unit 100 and the stacking unit 200, and an end of the extension 41 may be bonded to be fixed to a surface of the folding unit 100 or the stacking unit 200 to prevent shaking and improve durability against external impact. In addition, when an adhesive tape is additionally attached to fix the electrode assembly, the entire structure may be surrounded by the separator. Accordingly, a taping (taping) operation can be easily performed, and a taping method can be performed in various ways. For example, according to the eighth embodiment, the extension 41 of the separator 40 surrounds the entire structure, and then, a tape for reinforcing the fixing force may be attached to surround the entire electrode assembly. Here, the tape may be attached so as to be fixed in the entire length direction perpendicular to the width direction of the electrode assembly surrounded by the extension 41, rather than being fixed in the width direction. Alternatively, the tape may be attached to fix only the upper and lower ends of the electrode assembly or to surround the entire electrode assembly to be joined.

Further, according to the present invention, the stacked unit has a structure in which the electrode and the separator are bonded to each other, and the folded unit has a structure in which the separator and the electrode are not bonded to each other (movable in a horizontal direction perpendicular to the stacking direction). Therefore, in a state where the lamination unit 200 is laminated on the upper and lower portions of the folding unit 100, the alignment between the folding unit 100 and the lamination unit 20 can be adjusted before the taping or the entire hot press is performed. That is, since each of the electrodes and the separators are not bonded to each other in the folding unit 100, some movement between the folding unit 100 and the stacking unit 200 may be allowed to be uniformly arranged in the vertical direction after the folding unit 100 and the stacking unit are stacked. This may be a unique advantage of the present invention having a structure of stacking the stacking unit 200 in a state where the folding unit 100 is not fixed.

Although the embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.