KR20190099924A - Cylindrical Secondary Battery Comprising More Than Two Jelly-Roll Type Electrode Assembly and Manufacturing Method Thereof - Google Patents

Abstract

The present invention includes: a first wound-type electrode assembly which is wound in a state in which a positive electrode sheet, a separation sheet, a negative electrode sheet and a separation sheet are sequentially stacked; and a second wound-type electrode assembly which is formed in a cylindrical structure having a hollow part inside and is positioned to surround the outer surface of the first wound-type electrode assembly in a state of having the first wound-type electrode assembly inside. The second wound-type electrode assembly has a structure wound in a state in which a positive electrode sheet, a separation sheet, a negative electrode sheet and a separation sheet are sequentially stacked. The first wound-type electrode assembly and the second wound-type electrode assembly are in an independent structure but are connected in a series overall in a coupled state. The present invention provides a secondary battery of high voltage without increasing the size of the entire electrode assemblies.

Description

Cylindrical secondary battery comprising two or more wound electrode assemblies and a method of manufacturing the same {Cylindrical Secondary Battery Comprising More Than Two Jelly-Roll Type Electrode Assembly and Manufacturing Method Thereof}

The present invention relates to a cylindrical secondary battery comprising two or more wound electrode assemblies and a method for manufacturing the same, and specifically, a first wound electrode assembly having a cylindrical structure having an independent structure and an outer surface of the first wound electrode assembly. It relates to a cylindrical secondary battery and a method for manufacturing the same comprising a wound electrode assembly made in the form of an electrode assembly as a whole by connecting the second wound electrode assembly having a structure surrounding the series.

As development and demand for mobile devices increase, rechargeable batteries capable of charging and discharging are being used as energy sources for various mobile devices. Secondary batteries are attracting attention as energy sources such as electric vehicles and hybrid electric vehicles, which are proposed as alternatives to conventional gasoline and diesel vehicles using fossil fuels.

According to the shape of the battery case, secondary batteries are classified into cylindrical batteries and rectangular batteries in which the electrode assembly is embedded in a cylindrical or rectangular metal can, and pouch-type batteries in which the electrode assembly is embedded in a pouch type case of an aluminum laminate sheet. .

The electrode assembly embedded in the battery case is a power generator capable of charging and discharging composed of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode, and interposing a separator between a long sheet type positive electrode and a negative electrode coated with an active material. It is classified into a wound jelly-roll type and a stack type sequentially stacked with a separator between a plurality of positive and negative electrodes of a predetermined size. Among them, the jelly-roll type electrode assembly has advantages of easy manufacturing and high energy density per weight.

On the other hand, a plurality of secondary batteries are connected in series to a device requiring a high voltage. Since the number of batteries used in series connection increases in proportion to the size of the increased voltage, the overall battery pack size increases. As the number of units of batteries required for high voltage increases, it is difficult to apply a high voltage battery to a compact device. In addition, there is a need to manage a plurality of secondary batteries in one unit according to a required voltage.

Patent document 1 discloses a battery including an electrode assembly wound spirally while two cells are connected in series, but the cells have a structure in which a polymer electrolyte is interposed between a positive electrode and a negative electrode, and is continuous at an outer end of a cylindrical battery. As a structure in which the winding is performed, the above-mentioned problem cannot be solved in that the structure is increased in overall volume.

Patent Literature 2 discloses a secondary battery having a structure in which unit cells coupled to each other are accommodated in a pouch-type battery case. As a result, the thickness of the entire secondary battery is increased and applied to a cylindrical secondary battery having a high energy density. There is a problem that is a difficult structure.

As such, while it is possible to manufacture a high voltage battery pack including a cylindrical secondary battery having a high energy density as a unit cell, a clear solution for a technology capable of preventing an increase in the size of the overall battery pack has not been proposed until now. .

Republic of Korea Patent Publication No. 2001-0072615 Republic of Korea Patent Publication No. 2009-0051132

The present invention is to solve the above problems, an object of the present invention is to provide a secondary battery of a high voltage without increasing the size of the overall electrode assembly.

Winding electrode assembly according to the present invention for achieving this object,

A first wound electrode assembly having a structure in which a cathode sheet, a separator sheet, a cathode sheet, and a separator sheet are sequentially stacked; And

A second winding type electrode assembly formed of a cylindrical structure having a hollow formed therein and positioned to surround an outer surface of the first winding type electrode assembly with the first winding type electrode assembly located therein;

Including,

The second wound electrode assembly has a structure in which a cathode sheet, a separator sheet, a cathode sheet, and a separator sheet are sequentially stacked.

The first winding type electrode assembly and the second winding type electrode assembly may be independent of each other, but may be in the form of one electrode assembly that is connected in series as a whole.

That is, the wound electrode assembly according to the present invention, the first wound electrode assembly having a size smaller than the outer diameter of the conventional wound electrode assembly, and the hollow is formed therein and corresponds to the outer diameter of the conventional wound electrode assembly It comprises a second wound electrode assembly having a size, wherein the first wound electrode assembly is formed in the inner hollow of the second wound electrode assembly.

In addition, the first winding type electrode assembly and the second winding type electrode assembly have independent structures or structures connected in series with each other, so that the overall voltage is increased by the series connection.

Therefore, the overall appearance and size of the combined state of the first wound electrode assembly and the second wound electrode assembly correspond to the appearance and size of a conventional wound electrode assembly. Accordingly, it is possible to provide an electrode assembly and a secondary battery having increased voltage while maintaining the size of the electrode assembly.

The first winding type electrode assembly may have a structure in which a separation sheet surrounds an outer circumferential surface thereof, and electrical insulation may be maintained in a state in which the first winding type electrode assembly and the second winding type electrode assembly are coupled to each other.

In addition, the insulation may be further improved when the separation sheet is additionally wound on the inner surface of the second winding type electrode assembly.

On the other hand, in the case of using the first winding electrode assembly and the second winding electrode assembly having a structure independent of each other, as in the present invention, when any one electrode assembly is defective or damaged, defective or damaged electrode Only the assembly can be replaced, enabling economical use and shortening the time to repair damage.

In one specific example, the outer surface of the first wound electrode assembly and the inner surface of the second wound electrode assembly may be arranged adjacent to face each other, in order to minimize the reduction in capacity of the electrode assembly, the first winding It is preferable that the outer surface of the electrode assembly and the inner surface of the second winding type electrode assembly are arranged to be in contact with each other.

The wound electrode assembly may be connected in series between a first wound electrode assembly and a second wound electrode assembly. The first wound electrode assembly may be attached to protrude upward from the positive electrode tab and the negative electrode tab. The wound electrode assembly is attached such that the positive electrode tab protrudes upward and the negative electrode tab protrudes downward.

That is, the negative electrode tab of the first wound electrode assembly is configured to be coupled to the positive electrode tab of the second wound electrode assembly, and the positive electrode tab of the first wound electrode assembly is coupled to the positive electrode terminal, The negative electrode tab of the two-wound electrode assembly can be connected to an external device in combination with the negative electrode terminal.

In one specific example, a clad member may be interposed between the negative electrode tab and the positive electrode tab, and the clad member may have a structure in which a copper part facing the negative electrode tab and an aluminum part facing the positive electrode tab are combined.

As described above, since the clad member consisting of the copper part and the aluminum part is used, the problem of inferior weldability between the negative electrode tab made of a copper material and the positive electrode tab made of an aluminum material can be solved.

The first wound electrode assembly and the second wound electrode assembly according to the present invention may be assembled after being wound independently at the same time because the electrode tabs protruding upward or downward protrude. On the other hand, Patent Literature 1 has a disadvantage in that it takes a long time for the whole winding because it must be continuously wound for serial connection.

The wound electrode assembly may include a first winding electrode assembly and a second winding electrode assembly coupled in series, and the voltage of the wound electrode assembly may correspond to a voltage of the first winding electrode assembly and the second winding type. It may be formed equal to the sum of the voltage of the electrode assembly.

The voltage of the first winding type electrode assembly and the voltage of the second winding type electrode assembly may be identical to each other, and may be different. When using electrode assemblies having different voltages, secondary batteries having various voltages may be used. In the case of assembling and using electrode assemblies having the same voltage, the design of the battery voltage can be made uniform, thereby simplifying the process.

The wound electrode assembly may include a third wound electrode having a structure wound around the outer surface of the second wound electrode assembly in order to provide a battery having a high voltage while maintaining a constant size of the wound electrode assembly. Further comprising an assembly, wherein the first wound electrode assembly and the second wound electrode assembly are attached such that the positive electrode tab and the negative electrode tab protrude upward, and the third winding electrode assembly protrudes upward and the negative electrode tab protrudes. The tab may be a structure attached to protrude downward.

As described above, when the first winding type electrode assembly and the second winding type electrode assembly are additionally added, or the third winding type electrode assembly is added, the overall shape of the electrode assembly may be kept constant. And increasing the width of the separation sheet to manufacture an electrode assembly having a length in the winding axis direction of the wound electrode assembly.

In such a case, when a series connection is performed in a state in which a winding type electrode assembly having a constant length in a winding axis direction is stored in a battery case, a structure in which a cap assembly is coupled to each of a plurality of secondary batteries is used. By storing the electrode assembly having an extended length in the axial direction in the battery case, it is possible to prevent the unnecessary length from being extended than the structure in which one cap assembly is combined.

The present invention can also provide a cylindrical secondary battery that the wound electrode assembly is included in the battery case together with the electrolyte.

The cylindrical secondary battery may have a structure in which a positive electrode tab of the first wound electrode assembly is coupled to a cap assembly, and a negative electrode tab of the second wound electrode assembly is coupled to the battery case.

The present invention may also provide a battery pack including the cylindrical secondary battery as a unit cell.

Specifically, the battery pack may be used as a power source of a device requiring high temperature safety, long cycle characteristics, high rate characteristics, and the like, and a detailed example of such a device may include a mobile device and a wearable device. A power tool that is driven by an electric motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like; Electric motorcycles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf carts; An energy storage system and the like, but are not limited thereto.

Since the structure of these devices and their fabrication methods are known in the art, detailed description thereof is omitted herein.

The present invention also provides a method for producing the wound electrode assembly,

(a) sequentially stacking and winding the positive electrode sheet, the separating sheet, the negative electrode sheet, and the separating sheet to manufacture a first wound electrode assembly;

(b) sequentially stacking and winding the positive electrode sheet, the separator sheet, the negative electrode sheet, and the separator sheet to manufacture a second wound electrode assembly; And

(c) coupling the negative electrode tab of the first wound electrode assembly and the positive electrode tab of the second wound electrode assembly;

It may include.

That is, in the wound electrode assembly according to the present invention, the first wound electrode assembly and the second wound electrode assembly are manufactured independently of each other, and then an electrical connection is made through the bonding between them. It can be shortened and can be designed such that the overall size of the wound electrode assembly is not larger than that of the conventional wound electrode assembly.

The inner diameter of the second winding type electrode assembly may be the same as or larger than the outer diameter of the first winding type electrode assembly, such that the first winding type electrode assembly may be inserted into a central portion of the second winding type electrode assembly. When the space between the first winding type electrode assembly and the second winding type electrode assembly is formed, a space that is wasted unnecessaryly is formed in the dead space, the first winding type electrode assembly and the second winding type The electrode assembly is preferably arranged in close contact.

In the step (c), the welding may proceed in a state where the clad member is interposed between the negative electrode tab and the positive electrode tab. When the clad member is formed of a structure in which a copper part and an aluminum part are combined, they are made of different materials. The weldability between a positive electrode tab and a negative electrode tab can be prevented from falling.

As described above, the wound electrode assembly and the cylindrical secondary battery including the same according to the present invention has a structure in which a cylindrical first wound electrode assembly is accommodated inside a second wound electrode assembly having a hollow tube shape. The first wound electrode assembly and the second wound electrode assembly are connected in series to form a wound electrode assembly as a whole, and the outer diameter of the second wound electrode assembly may be changed to that of the conventional wound electrode assembly. When matching the outer diameter, it is possible to provide an electrode assembly having a high voltage and a cylindrical secondary battery including the same while maintaining the size of the overall electrode assembly.

Therefore, there is an advantage that the battery pack structure including the cylindrical secondary battery used as a unit cell can be used as it is.

In addition, the first winding type electrode assembly and the second winding type electrode assembly according to the present invention have an advantage that the time required for manufacturing can be shortened because each can be independently and simultaneously manufactured due to the electrode tab protruding to the outside. .

1 is a perspective view illustrating a manufacturing process of a first winding type electrode assembly.
2 is a perspective view illustrating a manufacturing process of a second wound electrode assembly.
3 is a perspective view illustrating a coupling process between a first wound electrode assembly and a second wound electrode assembly;
4 is a perspective view illustrating a state in which the first winding type electrode assembly and the second winding type electrode assembly are coupled to each other.
5 is an exploded view of a cladding between electrode tabs.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention may be easily implemented by those skilled in the art with reference to the accompanying drawings. However, in describing in detail the operating principle of the preferred embodiment of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In addition, the same reference numerals are used for parts having similar functions and functions throughout the drawings. Throughout the specification, when a part is connected to another part, this includes not only the case where it is directly connected, but also the case where it is indirectly connected with another element in between. In addition, the inclusion of any component does not exclude other components unless specifically stated otherwise, it means that may further include other components.

The present invention will be described in detail with reference to the drawings.

1 is a perspective view illustrating a manufacturing process of a first winding type electrode assembly.

Referring to FIG. 1, the first wound electrode assembly 100 has a structure in which a positive electrode sheet 110, a separation sheet 130, a negative electrode sheet 120, and a separation sheet 130 are sequentially stacked. Is done. Although omitted in FIG. 1, a positive electrode tab or a negative electrode tab is attached to at least one end of the positive electrode sheet 110 and the negative electrode sheet 120, and an electrode mixture layer is formed at a portion to which the positive electrode tab and the negative electrode tab are attached. The uncoated portion which is not formed is formed, and the electrode mixture layer is formed in the remaining portion.

The first wound electrode assembly 100 may be formed in a cylindrical shape and may be positioned at the center of the second wound electrode assembly of FIG. 2.

2 is a perspective view illustrating a manufacturing process of a second wound electrode assembly.

Referring to FIG. 2, the second wound electrode assembly 200 has a structure in which a positive electrode sheet 210, a separation sheet 230, a negative electrode sheet 220, and a separation sheet 230 are sequentially stacked. Is done. Although omitted in FIG. 2, a positive electrode tab or a negative electrode tab is attached to at least one end of the positive electrode sheet 210 and the negative electrode sheet 220, and an electrode mixture layer is formed at a portion to which the positive electrode tab and the negative electrode tab are attached. The uncoated portion which is not formed is formed, and the electrode mixture layer is formed in the remaining portion.

The second winding-type electrode assembly 200 is formed in a tube shape having an inner center as a whole so as to insert the first winding-type electrode assembly 100.

FIG. 3 illustrates a process of combining the first wound electrode assembly and the second wound electrode assembly, and FIG. 4 illustrates a state in which the first wound electrode assembly and the second wound electrode assembly are coupled to each other.

3 and 4, in the first winding type electrode assembly 100, the positive electrode tab 111 and the negative electrode tab 121 protrude upward, and the second winding type electrode assembly 200 is the positive electrode tab 211. ) Protrudes upward, and the negative electrode tab 221 protrudes downward. Therefore, in a state in which the first winding type electrode assembly 100 and the second winding type electrode assembly 200 are coupled to each other, the negative electrode tab 121 of the first winding type electrode assembly 100 is the second winding type electrode assembly 200. Bar is disposed adjacent to the positive electrode tab 211, the coupling of the negative electrode tab 121 and the positive electrode tab 211 can be easily made. In addition, by the series connection as described above the overall voltage is to produce an electrode assembly having a voltage of the same size as the sum of the voltage of the first wound electrode assembly 100 and the voltage of the second wound electrode assembly 200.

The positive electrode tab 111 of the first wound electrode assembly 100 is coupled with a positive electrode terminal, and the negative electrode tab 221 of the second wound electrode assembly 200 is coupled with a negative electrode terminal to form an electrode terminal of a cylindrical secondary battery. And the electrode terminal is coupled to an external device to supply power.

The outer diameter d1 of the first wound electrode assembly 100 may be the same as or smaller than the inner diameter d2 of the second wound electrode assembly 200, in consideration of the degree of expansion of the electrode assemblies. Can be designed to an appropriate size.

5 is an exploded view of a cladding between electrode tabs.

Referring to FIG. 5, when the positive electrode tab 211 and the negative electrode tab 121 are made of different materials, weldability may be lowered due to material characteristics. As shown in FIG. 5, the positive electrode tab 211 and the negative electrode tab 121 are formed. When welding in a state where the clad member 230 is interposed therebetween, the bonding force between the positive electrode tab 211 and the aluminum portion 231 of the clad member and the negative electrode tab 121 and the copper portion 232 of the clad member is improved. Since it can be, it is possible to prevent problems due to poor welding.

Those skilled in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

100: first winding electrode assembly
110, 210: anode sheet
111, 211: positive electrode tab
120, 220: cathode sheet
121, 221: negative electrode tab
130, 230: Separation Sheet
200: second winding electrode assembly
300: wound electrode assembly
230: clad member
231 aluminum part
232: copper section
d1: outer diameter of the first winding type electrode assembly
d2: inner diameter of the second wound electrode assembly

Claims (12)

A first wound electrode assembly having a structure in which a cathode sheet, a separator sheet, a cathode sheet, and a separator sheet are sequentially stacked; And
A second winding type electrode assembly formed of a cylindrical structure having a hollow formed therein and positioned to surround an outer surface of the first winding type electrode assembly with the first winding type electrode assembly located therein;
Including,
The second wound electrode assembly has a structure in which a cathode sheet, a separator sheet, a cathode sheet, and a separator sheet are sequentially stacked.
The first winding type electrode assembly and the second winding type electrode assembly have independent structures from each other, but in a combined state, a wound type electrode assembly having a form of one electrode assembly connected as a whole in series. The wound electrode assembly of claim 1, wherein an outer surface of the first wound electrode assembly and an inner surface of the second wound electrode assembly are adjacent to each other. The method of claim 1, wherein the first wound electrode assembly is attached so that the positive electrode tab and the negative electrode tab protrudes upward,
The second wound electrode assembly may have a positive electrode tab upwardly protruding and a negative electrode tab protruding downwardly. The wound electrode assembly of claim 1, wherein the negative electrode tab of the first wound electrode assembly is coupled to the positive electrode tab of the second wound electrode assembly. The method of claim 4, wherein a clad member is interposed between the negative electrode tab and the positive electrode tab,
The clad member is a wound electrode assembly having a structure in which a copper portion facing the negative electrode tab and an aluminum portion facing the positive electrode tab are combined. The wound electrode assembly of claim 1, wherein the voltage of the wound electrode assembly is equal to the sum of the voltage of the first wound electrode assembly and the voltage of the second wound electrode assembly. The method of claim 1, further comprising a third wound electrode assembly having a structure wound around the outer surface of the second wound electrode assembly,
The first winding type electrode assembly and the second winding type electrode assembly are attached to protrude upward from the positive electrode tab and the negative electrode tab,
The wound electrode assembly of claim 3, wherein the positive electrode tab protrudes upward and the negative electrode tab protrudes downward. A cylindrical secondary battery comprising the wound electrode assembly according to any one of claims 1 to 7 together with an electrolyte in a battery case. The cylindrical secondary battery of claim 8, wherein the positive electrode tab of the first wound electrode assembly is coupled to a cap assembly, and the negative electrode tab of the second wound electrode assembly is coupled to the battery case. A method of manufacturing a wound electrode assembly according to any one of claims 1 to 7,
(a) sequentially stacking and winding the positive electrode sheet, the separating sheet, the negative electrode sheet, and the separating sheet to manufacture a first wound electrode assembly;
(b) sequentially stacking and winding the positive electrode sheet, the separator sheet, the negative electrode sheet, and the separator sheet to manufacture a second wound electrode assembly; And
(c) coupling the negative electrode tab of the first wound electrode assembly and the positive electrode tab of the second wound electrode assembly;
Method for producing a wound electrode assembly comprising a. The method of claim 10, wherein the inner diameter of the second winding electrode assembly is formed to be the same as or larger than the outer diameter of the first winding electrode assembly, the first winding electrode assembly in the center of the second winding electrode assembly Method for producing a wound electrode assembly to be inserted. The method of claim 10, wherein in step (c), welding is performed while a clad member is interposed between the negative electrode tab and the positive electrode tab.

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