KR20130103202A - Electrode assembly and rechargeable battery with the same - Google Patents

Abstract

PURPOSE: An electrode assembly is provided to improve the productivity of an electrode-laminating process and to improve cell stability. CONSTITUTION: An electrode assembly includes a band-like first electrode (10) having a first active material in a first current collector; a separator (30) covering one end of the first electrode and is overlapped on both sides of the first electrode; and a plate-like second electrode (20) having a second active material in a second current collector. The second electrode is laminated on the separator, and the second electrode is wound by the separator several times in a state the first electrode is mounted.

Description

Electrode assembly and secondary battery including same {ELECTRODE ASSEMBLY AND RECHARGEABLE BATTERY WITH THE SAME}

The present invention relates to an electrode assembly suitable for medium and large size and a secondary battery comprising the same.

The secondary battery market is centered on small batteries used in mobile devices such as laptops and mobile phones. Globally, environmental regulations and green policies are being strengthened due to environmental pollution and increased energy costs due to the fossil fuel resource (mining and mining).

Currently, most of the energy sources used in the development of electric vehicles are medium and large lithium secondary batteries, and are being developed based on these. In the future, research on medium-large-sized lithium secondary batteries is expected to be conducted as an energy storage medium in the field of power storage associated with renewable energy and smart grid.

For example, the secondary battery includes an electrode assembly including a stack or winding of a positive electrode, a negative electrode, and a separator, and a metal case or pouch containing the electrode assembly and an electrolyte.

In the small secondary battery having a small size of the negative electrode and the positive electrode, handling of the electrode is easy, and productivity for the lamination and winding processes may be relatively easily secured. However, in the medium and large secondary batteries, improvement of productivity and securing stability in the process of stacking and winding the positive electrode, the separator, and the negative electrode remain a major challenge.

In other words, when developed into a medium-large secondary battery, the thickness of the electrode becomes thin, and as the size of the electrode becomes large, the handling of the electrode becomes difficult, and the productivity of the lamination and winding processes becomes difficult.

In addition, during the cutting of the electrode, the coated active material is detached or a large amount of foreign substances such as a current collector are generated, and thus a large amount of foreign substances may be inserted in the lamination and winding processes of the electrode, thereby causing a short inside the electrode assembly. Can be. That is, the secondary battery may be defective and the secondary battery may be exploded.

It is an object of the present invention to provide an electrode assembly in which the productivity is improved and the stability of the cell is improved in the electrode stacking process.

An object of the present invention is to provide an electrode assembly suitable for medium and large size, and to provide a secondary battery including the electrode assembly.

An electrode assembly according to an embodiment of the present invention includes a first electrode on a band having a first active material on a first current collector, and formed on a band to surround one end of the first electrode and overlap both surfaces of the first electrode. And a second electrode on a plate having a separator and a second active material in a second current collector, wherein the second electrode is stacked on the separator covering the first electrode, and the first electrode is embedded therein. The process of winding the second electrode with a separator is repeatedly performed to form a stacked structure of the first electrode, the separator, and the second electrode.

The first electrode may form a spiral structure.

The first electrode may form a planar portion corresponding to both surfaces of the second electrode and a curved portion corresponding to an end portion of the second electrode.

The separation membrane may correspond to the first electrode, and may include a planar portion corresponding to both surfaces of the second electrode and a curved portion corresponding to an end portion of the second electrode.

The curved portion of the separator may be formed in two layers on one side of the curved portion of the first electrode.

The uncoated portion of the first electrode and the uncoated portion of the second electrode may be disposed opposite to each other.

The uncoated portion of the first electrode and the uncoated portion of the second electrode may be disposed on the same side.

The electrode assembly according to an embodiment of the present invention comprises the steps of stacking a second electrode on a first separator covering the first electrode, and winding the second electrode with the first separator in a state in which the first electrode is embedded. Repeatedly performed, a unit electrode assembly for forming a stacked structure of the first electrode, the first separator and the second electrode, and a plurality of unit electrode assemblies are stacked to provide a plurality of unit electrode assemblies provided between the unit electrode assemblies 2 separator.

In the unit electrode assembly, the first separator may be formed as one and wind one end of the first electrode, and may be connected to both ends at the other end of the first electrode.

In the electrode assembly according to the exemplary embodiment, a second electrode may be further disposed between two unit electrode assemblies to be stacked and between one side unit electrode assembly and the second separator.

The second separator may further extend outside the plurality of unit electrode assemblies to surround the entire plurality of unit electrode assemblies.

In the unit electrode assembly, the first separator is formed as one to wind one end of the first electrode, connect one end of the first separator to the first separator from the other end of the first electrode, and connect the second electrode to one. The other end of the first separator may be connected to the first separator by being stacked and wrapped.

The electrode assembly according to the exemplary embodiment of the present invention may further include a third separator surrounding the entire plurality of unit electrode assemblies stacked.

The uncoated portion of the first electrode and the uncoated portion of the second electrode may be disposed opposite to each other.

The uncoated portion of the first electrode and the uncoated portion of the second electrode may be disposed on the same side.

According to an embodiment of the present invention, a secondary battery includes a first electrode on a band having a first active material in a first current collector, and is formed in a band shape to surround one end of the first electrode and to overlap both surfaces of the first electrode. And a second electrode on a plate having a separator and a second active material in a second current collector, wherein the second electrode is stacked on the separator covering the first electrode, and the first electrode is embedded therein. Repeating the process of winding the second electrode with a separator, an electrode assembly for stacking the first electrode, the separator and the second electrode, a case containing the electrode assembly and the electrolyte, and the first electrode and the first And a first electrode tab and a second electrode tab connected to each of the two electrodes and drawn out of the case.

The separator includes a planar portion corresponding to both surfaces of the second electrode and a curved portion corresponding to an end portion of the second electrode, corresponding to the first electrode, and the curved portion of the separator is formed of the first electrode. Two layers may be formed on one side of the curved portion.

According to an exemplary embodiment of the present invention, a secondary electrode is stacked on a first separator covering a first electrode, and the second electrode is wound around the first separator with the first electrode embedded therein. By repeating, the first electrode, the first separator and the second electrode is formed by stacking the second electrode, a plurality of unit electrode assembly, and a plurality of the unit electrode assembly, the second separator provided between the unit electrode assembly A case including the unit electrode assemblies, the second separator and the electrolyte, and a first electrode tab connected to the first electrode and the second electrodes of the unit electrode assemblies and drawn out of the case; And two electrode tabs.

As described above, according to an embodiment of the present invention, the second electrode is stacked on the separator having the first electrode (cathode) embedded therein, and the process of winding the second electrode (anode) with the separator is repeated, so that the first electrode and the separator are And by forming the laminated structure of a 2nd electrode, productivity improves and stability improves in the lamination process of an electrode.

In addition, an embodiment of the present invention, by stacking a plurality of unit assemblies using such an electrode assembly as a unit electrode assembly can easily implement an electrode assembly and a secondary battery comprising the same for medium and large.

1 is a perspective view showing a start state of a process of manufacturing an electrode assembly used in a secondary battery according to a first embodiment of the present invention.
2 is a cross-sectional view illustrating a process of manufacturing an electrode assembly used in a secondary battery according to a first embodiment of the present invention.
3 is a perspective view of an electrode assembly manufactured by the process of FIG. 2.
4 is a cross-sectional view of a rechargeable battery including the electrode assembly of FIG. 3.
5 is a cross-sectional view of a medium-large electrode assembly according to a second exemplary embodiment in which the electrode assemblies of FIG. 3 are stacked.
6 is a cross-sectional view of a medium-large electrode assembly according to a third exemplary embodiment in which the electrode assemblies of FIG. 3 are stacked.
7 is a perspective view illustrating a start state of a process of manufacturing an electrode assembly used in a secondary battery according to a fourth embodiment of the present invention.
8 is a cross-sectional view illustrating a process of manufacturing an electrode assembly used in a secondary battery according to a fourth embodiment of the present invention.
9 is a perspective view of an electrode assembly manufactured from the process of FIG. 8.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

1 is a perspective view showing a start state of a process of manufacturing an electrode assembly used in a secondary battery according to a first embodiment of the present invention, Figure 2 is an electrode assembly used in a secondary battery according to a first embodiment of the present invention 3 is a cross-sectional view showing a step of manufacturing a, Figure 3 is a perspective view of the electrode assembly manufactured by the process of FIG.

1 to 3, the electrode assembly 100 includes a first electrode 10 (eg, a cathode), a separator 30, and a second electrode 20 (eg, an anode). do. The separator 30 may be formed of a polymer solid electrolyte film through which lithium ions pass.

4 is a cross-sectional view of the rechargeable battery 300 including the electrode assembly 100 of FIG. 3. Referring to FIG. 4, the secondary battery 300 of the first embodiment includes an electrode assembly 100 for charging and discharging and a case containing an electrolyte. For convenience, the pouch 200 is illustrated as a case.

The negative electrode 10 includes a coating part 11 coated with the first active material on the first current collector of the metal thin film, and a plain part 12 set as the first contact body exposed by not applying the first active material. The first electrode tab (for convenience, referred to as a "cathode tab") 42 may be connected by welding to the uncoated portion 12 of the cathode 10.

The positive electrode 20 includes a coating portion 21 coated with a second active material on a second current collector of a metal thin film, and a plain portion 22 set as a second contact body exposed by not applying the second active material. The second electrode tab (for convenience, referred to as “anode tab”) 52 may be connected by welding to the uncoated portion 22 of the positive electrode 20.

Since the second active material uses a higher molecular weight binder than the first active material, the coating part 21 of the positive electrode 20 is formed to be twice as thick as the coating part 11 of the negative electrode 10, Has a harder nature.

The uncoated portion 12 of the cathode 10 and the uncoated portion 22 of the anode 20 are disposed on opposite sides of each other. The negative electrode tab 42 and the positive electrode tab 52 connected to each of the plain portions 12 and 22 are respectively drawn out to the opposite sides of the electrode assembly 100.

The pouch 200 may be formed in a multilayer sheet structure surrounding the outside of the electrode assembly 100. For example, the pouch 200 may include a polymer sheet insulated and thermally fused, a composite nylon sheet forming and protecting an outer surface, and a metal sheet provided therebetween to impart mechanical strength.

Referring back to FIGS. 1 and 2, the cathode 10 is formed in a band shape, and the separator 30 is formed in a band shape to surround one end of the cathode 10 in the longitudinal direction and overlap the both surfaces of the cathode 10. The cathode 10 and the separator 30 may be adhered to each other. The separator 30 adhered to both surfaces of the negative electrode 10 supports the thin and large-area negative electrode 10 to provide mechanical strength to the large negative electrode. That is, torn or crumpled by the separator 30 of the cathode 30 may be prevented.

The anode 20 is formed in a plate shape and is laminated on one surface of the separator 30 superimposed on the cathode 10 (FIG. 2A). At this time, the alignment of the positive electrode 20 and the negative electrode 10 is completed by matching the vertical alignment of the positive electrode 20 with respect to the negative electrode 10. Therefore, it is advantageous in terms of the productivity of the lamination process, and it is unlikely that the alignment of the anodes 10 and 20 is disturbed, and the stability of the cell including the electrode assembly 100 may be improved. Then, the uncoated portions 12, 22 of the anodes 10, 20 are disposed on opposite sides with respect to the width direction (Fig. 1).

In addition, since the cathode 10 is formed in a band shape, it is not cut as many as the number of the anodes 20. Therefore, compared with the case where the negative electrode 10 is formed in a plate shape, it minimizes foreign matters that may be generated when cutting one by one, and simplifies the cleaning process.

The positive electrode 20 is wound by the separator 30 with the negative electrode 10 embedded therein (FIG. 2A). Therefore, the separator 30 containing the negative electrode 10 is disposed on both sides of the positive electrode 20 (FIG. 2B).

The plate-shaped anode 201 is further laminated on one surface of the separator 30 wound around the anode 20 (FIG. 2B), and the anode 201 is wound on the separator 30 (FIG. 2B). ). Therefore, the separator 30 is disposed outside the anodes 20 and 201 (FIG. 2C).

The anode 202 is further stacked on the outer surface of the separator 30 (FIG. 2C), and the winding process may be repeatedly performed. Since the separator 30 is adhered to the cathode 10, the upper portion of the separator 30 may be finished with the anode 202. That is, the electrode assembly 100 as shown in FIG. 3 may be completed by repeatedly laminating and winding the anodes 20, 201 and 202 on the outer surface of the separator 30.

In this case, by repeatedly winding the cathode 10 and the separator 30 containing the same in one direction, the cathode 10 may form a spiral structure. In addition, the separator 30 forms a spiral structure on both sides of the cathode 10.

Referring to FIG. 2, the cathode 10 forms a planar portion 10a corresponding to both surfaces of the anode 20 and a curved portion 10b corresponding to an end portion of the anode 20. Accordingly, the separator 30 overlapped with the cathode 10 forms the planar portion 30a and the curved portion 30b corresponding to the cathode 10.

That is, the planar portion 30a of the separator 30 is disposed to correspond to both sides of the cathode 10 planar portion 10a, and the curved portion 30b is the curved portion of the cathode 10 positioned at the end of the anode 20. It is arrange | positioned corresponding to both surfaces of 10b.

Therefore, the curved portions 30b of the separator 30 are disposed in two layers on one side of the curved portion 10b of the cathode 10. At this time, the anode 20 has only an end portion without forming a curved portion corresponding to the curved portion 30b of the separator 30. That is, the positive electrode 20 may not be stressed at the curved portions 30b and 10b of the separator 30 and the negative electrode 10, and the detachment of the coating portion 21 of the second active material may be prevented.

Meanwhile, the electrode assembly 100 may be provided as one, as shown in FIG. 4, to form the secondary battery 300, and as described below, the electrode assembly 100 may be used in a plurality of stacked structures to form a medium-large electrode assembly 400 or 500. ) May be formed.

5 is a cross-sectional view of a medium-large electrode assembly 400 according to a second embodiment in which the electrode assemblies 100 of FIG. 3 are stacked. For convenience, the electrode assembly 100 of FIGS. 1 to 4 in the medium-large electrode assembly 400 is called a unit electrode assembly, and the separator 30 of the unit electrode assembly is called a first separator.

Referring to FIG. 5, the medium-large electrode assembly 400 of the second embodiment includes a unit electrode assembly 100 stacked in plurality, and a second separator 230 provided between the unit electrode assemblies 100.

In this case, in the unit electrode assembly 100, the first separator 30 is formed as one to wind one end of the cathode 10 and connect both ends to each other at the other end of the cathode 10. That is, since the first separator 30 is covered on both sides of the cathode 10 in the longitudinal direction, the short circuit with the anode 20 is prevented.

The second separator 230 is provided between the unit electrode assemblies 100, and further extends outside the plurality of unit electrode assemblies 100 to surround and fix the entire unit electrode assemblies 100.

In this case, the anode 202 may be disposed between the two unit electrode assemblies 100 stacked between the one side electrode assembly 100 and the second separator 230. By disposing the anode 202 between the cathodes 10 of the neighboring unit electrode assembly 100, the medium-large electrode assembly 400 may further increase the capacity.

6 is a cross-sectional view of a medium-large electrode assembly 500 according to a third embodiment in which the electrode assemblies 100 of FIG. 3 are stacked. Referring to FIG. 6, in the unit electrode assembly 100 of the medium-large electrode assembly 500 of the third embodiment, the first separator 30 is formed as one to wind one end of the cathode 10 and the other of the cathode 10. At one end, one end of the first separator 30 is connected to the first separator 30 (C1), and one more anode 202 is stacked and wrapped to wrap the other end of the first separator 30 with the first separator 30. (C2).

To this end, it is formed short on one surface of the cathode 10 of the first separation membrane 30 and long on the other surface. On the long side, the first separator 30 is connected to the first separator 30 by wrapping the anode 202 further stacked (C2).

The medium-large electrode assembly 500 of the third embodiment surrounds the entire unit electrode assemblies 100 stacked on the third separator 330. The third separator 330 bundles the unit electrode assemblies 100 to fix one cell.

The medium and large electrode assemblies 400 and 500 of the second and third embodiments disclosed above are accommodated in a case together with an electrolyte and drawn out of the case through positive and negative electrode tabs, thereby forming a medium and large secondary battery.

7 is a perspective view illustrating a start state of a process of manufacturing an electrode assembly 600 used in a secondary battery according to a fourth embodiment of the present invention, and FIG. 8 is used in a secondary battery according to a fourth embodiment of the present invention. It is sectional drawing which shows the process of manufacturing the electrode assembly 600 used. 9 is a perspective view of an electrode assembly 600 fabricated starting with the process of FIG. 8.

7 to 9, the electrode assembly 600 includes a cathode 610, a separator 630, and an anode 620. For convenience, the separator 630 is omitted in FIG. 8.

The negative electrode 610 includes a coating part 611 coated with the first active material on the first current collector of the metal thin film, and a plain part 612 set as the first contact body exposed by not applying the first active material. The negative electrode tab 642 may be connected to the uncoated portion 612 of the negative electrode 610 by welding.

The anode 620 includes a coating part 621 having a second active material coated on a second current collector of a metal thin film, and a plain part 622 which is set as a second contact body exposed by not applying the second active material. The positive electrode tab 652 may be welded to the plain portion 622 of the positive electrode 620.

The cathode 610 is formed in a band shape, and the separator 630 is formed in a band shape to surround one end of the cathode 610 in the longitudinal direction and overlap the both surfaces of the cathode 610.

The anode 620 is formed in a plate shape and is stacked on one surface of the separator 630 superimposed on the cathode 610. At this time, the uncoated portions 612 and 622 of the anodes 610 and 620 are disposed on the same side with respect to the width direction.

When the positive electrode 620 is wound around the negative electrode 610 in this state, the negative electrode 610 is disposed on both sides of the positive electrode 620 (the separator is omitted in FIG. 8). The plate-shaped anode 640 is further stacked on one side of the cathode 610 wound around the anode 620, and the anode 660 is wound around the cathode 610. This manufactures the electrode assembly 600.

The uncoated portion 612 is formed by maintaining a first gap D1 and a second gap D2 set along the length of the cathode 610. In the electrode assembly 600, the first gap D1 may be spaced apart from the uncoated portion 622 of the anode 620 in correspondence with the planar portion, and the second gap D2 may correspond to the curved portion of the cathode 610. Enable bonding of adjacent uncoated parts 612.

Accordingly, the first and second gaps D1 and D2 of the non-coating portion 612 may be configured to increase the volume of the electrode assembly 600 as the cathode 610 is wound around the separator 630 and the anode 620. Can be set. For example, the first interval D1 is set the same, and the second interval D2 is set to increase gradually as the number of turns increases.

The uncoated portion 612 of the cathode 610 and the uncoated portion 622 of the positive electrode 620 are disposed on the same side. The negative electrode tab 642 and the positive electrode tab 652 connected to each of the plain portions 612 and 622 are drawn out to the same side of the electrode assembly 600.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

10, 610: first electrode (cathode) 10a, 30a: flat part
10b, 30b: curved part 11, 21, 611, 621: coating part
12, 22, 612, 622: Plain part 20, 201, 202, 620, 640: Second electrode (anode)
30, 630: (first) separator 42, 642: negative electrode tab
52, 652: positive electrode tab 100, 600: electrode assembly
200: pouch 230: second separator
300: secondary battery 330: third separator
400, 500: medium and large electrode assembly

Claims (18)

A band-shaped first electrode including the first active material in the first current collector;
A separator formed in a band shape to surround one end of the first electrode and overlap the both surfaces of the first electrode;
Second electrode on plate having second active material in second current collector
/ RTI >
Stacking the second electrode on the separator covering the first electrode,
Repeating the process of winding the second electrode with the separator having the first electrode embedded therein,
The electrode assembly forming a stacked structure of the first electrode, the separator and the second electrode.
The method of claim 1,
And the first electrode forms a helical structure.
The method of claim 1,
The first electrode,
Planar portions corresponding to both surfaces of the second electrode;
And an curved surface portion corresponding to an end of the second electrode.
The method of claim 3,
The separator,
In response to the first electrode,
Planar portions corresponding to both surfaces of the second electrode;
And an curved surface portion corresponding to an end of the second electrode.
5. The method of claim 4,
The curved portion of the separator,
Electrode assembly formed in two layers on one side of the curved portion of the first electrode.
The method of claim 1,
The uncoated portion of the first electrode and the uncoated portion of the second electrode are disposed opposite to each other.
The method of claim 1,
The uncoated portion of the first electrode and the uncoated portion of the second electrode are disposed on the same side.
The second electrode is stacked on the first separator covering the first electrode, and the process of winding the second electrode with the first separator having the first electrode embedded therein is repeated to perform the first electrode and the first electrode. A unit electrode assembly forming a stacked structure of a separator and the second electrode; And
And a second separator provided between the unit electrode assemblies and provided between the unit electrode assemblies.
9. The method of claim 8,
In the unit electrode assembly, the first separator,
Is formed as one and winds up one end of the first electrode,
And an electrode assembly connected to each other at both ends at the other end of the first electrode.
10. The method of claim 9,
A second electrode is further disposed between the two unit electrode assemblies stacked between the one side electrode assembly and the second separator.
Electrode assembly.
The method of claim 10,
The second separation membrane,
An electrode assembly further extended outside the plurality of unit electrode assemblies to surround the entire plurality of unit electrode assemblies.
9. The method of claim 8,
In the unit electrode assembly, the first separator,
Is formed as one and winds up one end of the first electrode,
And connecting one end of the first separator to the first separator at another end of the first electrode, and stacking and wrapping one more second electrode to connect the other end of the first separator to the first separator.
The method of claim 12,
The electrode assembly further comprises a third separator surrounding the entire plurality of unit electrode assemblies stacked.
9. The method of claim 8,
The uncoated portion of the first electrode and the uncoated portion of the second electrode are disposed opposite to each other.
9. The method of claim 8,
The uncoated portion of the first electrode and the uncoated portion of the second electrode are disposed on the same side.
A first electrode on a band having a first active material on the first current collector, a separator formed on a band, surrounding one end of the first electrode and overlapping on both sides of the first electrode, and a second active material on the second current collector A second electrode on a plate including the plate; and stacking the second electrode on the separator covering the first electrode, and winding the second electrode with the separator in a state in which the first electrode is embedded. An electrode assembly stacking the first electrode, the separator, and the second electrode;
A case containing the electrode assembly and the electrolyte; And
A secondary battery comprising a first electrode tab and a second electrode tab connected to the first electrode and the second electrode, respectively, and drawn out of the case.
17. The method of claim 16,
The separator,
A flat portion corresponding to both surfaces of the second electrode and a curved portion corresponding to an end portion of the second electrode, corresponding to the first electrode,
The curved portion of the separator,
A secondary battery forming two layers on one side of the curved portion of the first electrode.
The second electrode is stacked on the first separator covering the first electrode, and the process of winding the second electrode with the first separator having the first electrode embedded therein is repeated to perform the first electrode and the first electrode. A unit electrode assembly formed by stacking a separator and the second electrode; And
A second separator provided with a plurality of unit electrode assemblies and provided between the unit electrode assemblies;
A case containing the unit electrode assemblies, the second separator, and an electrolyte; And
And a first electrode tab and a second electrode tab connected to the first electrode and the second electrodes of the unit electrode assemblies and drawn out of the case, respectively.

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