KR20230133619A - Electrode assembly for secondary battery, secondary battery comprising the same and manufacturing method thereof - Google Patents

Abstract

An electrode assembly for a secondary battery according to an embodiment of the present invention includes: an electrode assembly main body in which a positive electrode, a negative electrode, and a separator are stacked; and a self-pressing member disposed in a structure surrounding the outer portion of the electrode assembly main body to press the electrode assembly main body at a preset pressure.

Description

Electrode assembly for secondary batteries, secondary batteries including the same, and manufacturing method of secondary batteries {ELECTRODE ASSEMBLY FOR SECONDARY BATTERY, SECONDARY BATTERY COMPRISING THE SAME AND MANUFACTURING METHOD THEREOF}

The present invention relates to an electrode assembly for a secondary battery, a secondary battery including the same, and a method of manufacturing the secondary battery. More specifically, the present invention relates to a problem that occurs due to a gap between the cathode and the anode due to abnormally generated gas when using the secondary battery. It relates to an electrode assembly for a secondary battery that can effectively prevent this, a secondary battery including the same, and a method of manufacturing the secondary battery.

In general, as the development of the cutting-edge electronics industry makes it possible to reduce the size and weight of electronic equipment, the use of various types of mobile devices, including portable electronic devices, is increasing, and the use of electric vehicles or hybrid vehicles is also expanding. .

Recently, the need for batteries with high energy density as a power source for mobile devices, electric vehicles, or hybrid vehicles is increasing day by day. As a result, demand for high-performance secondary batteries is increasing, and research to improve the performance and safety of secondary batteries is also being actively conducted. In particular, recent secondary batteries are designed to have a very compact internal structure in accordance with trends such as higher performance, thinner thickness, and miniaturization.

However, during actual use of the secondary battery, gas may be generated inside the secondary battery for various reasons, and the gas may widen the gap between the cathode and anode of the electrode assembly. If the gap between the cathode and the anode is abnormally widened as described above, the internal resistance of the secondary battery increases, causing a problem of interruption of current flow. Therefore, technology that can prevent the gap between the cathode and anode from widening even when gas is generated inside the secondary battery is continuously being researched and developed.

Related prior art documents include Korea Patent Publication No. 10-2020-0125194 (Title of invention: Secondary battery internal gas collection device, Publication date: 2020.11.04) and Korean Patent Publication No. 10-2012-0108677 (Title of invention : There is a pouch-type secondary battery including a gas emission device and a gas emission control method, publication date: 2012.10.05).

Korean Patent Publication No. 10-2020-0125194 (published on November 4, 2020) Korean Patent Publication No. 10-2012-0108677 (published on October 5, 2012)

An embodiment of the present invention provides an electrode assembly for a secondary battery that can effectively prevent problems caused by a gap occurring between the cathode and anode of the electrode assembly due to gas abnormally generated inside the secondary battery, a secondary battery including the same, and A method for manufacturing a secondary battery is provided.

In addition, the embodiment of the present invention uses a structure that holds the cathode and anode of the electrode assembly to prevent the gap between the cathode and anode from widening due to gas, and the structure can be easily used in secondary batteries with a very inexpensive and simple structure. Provides an electrode assembly for a secondary battery that can be applied, a secondary battery including the same, and a method for manufacturing the secondary battery.

According to one embodiment of the present invention, an electrode assembly body in which a cathode, an anode, and a separator are stacked, and a self-pressing member disposed in a structure surrounding the outer portion of the electrode assembly body to press the electrode assembly body at a preset pressure. Provided is an electrode assembly for a secondary battery comprising:

Preferably, the self-pressing member may be provided as a heat shrinkable tube that shrinks by heat. Here, the electrode assembly body may be arranged to be accommodated inside the heat shrinkable tube. Additionally, the heat shrinkable tube may be heat-shrinked to press the outer surface of the electrode assembly body to a preset pressure.

Preferably, the electrode assembly body may include a plurality of stacked cathodes, anodes stacked so as to be respectively disposed between the cathodes, and a separator respectively disposed between the anodes and the cathodes.

The self-pressing member may press the electrode assembly body with a preset pressure along a stacking direction of the cathode, the anode, and the separator.

Preferably, a negative electrode tab may protrude from one side of the cathode, and a positive electrode tab may protrude from one side of the positive electrode. Therefore, the self-pressing member may be provided with an opening through which the negative electrode tab and the positive electrode tab are disposed.

According to another aspect of the present invention, there is provided a secondary battery including the electrode assembly as described above, a case in which the electrode assembly is stored, and an electrolyte solution injected into the case.

According to another aspect of the present invention, preparing an electrode assembly body by laminating a cathode, an anode, and a separator, completing the electrode assembly by applying a self-pressing member to the electrode assembly body, and placing the electrode assembly inside the case. A method of manufacturing a secondary battery is provided, including storing the battery in a case and injecting an electrolyte into the case.

Here, the self-pressing member may be provided as a heat shrinkable tube that shrinks by heat. At this time, the step of completing the electrode assembly includes placing the electrode assembly body inside the heat shrink tube, applying heat to the heat shrink tube to heat the heat shrink tube. It may include a step of shrinking, and a step of removing heat applied to the heat shrinkable tube when the heat shrinkable tube is pressed to an outer surface of the electrode assembly body at a preset pressure.

In addition, in the step of disposing the electrode assembly body, the negative electrode tab protruding on one side of the cathode and the positive electrode tab protruding on one side of the positive electrode are passed through the opening formed in the heat shrinkable tube so as not to interfere with the heat shrinkable tube. can be placed.

The electrode assembly for a secondary battery according to an embodiment of the present invention, a secondary battery including the same, and a method of manufacturing a secondary battery include a gap occurring between the cathode and the anode of the electrode assembly due to gas abnormally generated inside the secondary battery. Problems can be effectively prevented.

In addition, the electrode assembly for a secondary battery, the secondary battery including the same, and the manufacturing method of the secondary battery according to an embodiment of the present invention include a self-pressing member that stably holds the electrode assembly by pressurizing the cathode, positive electrode, and separator of the electrode assembly by itself. By adding to the electrode assembly, the gap between the cathode and the anode can be prevented from widening due to gas with a simple structure, and this can be applied very inexpensively and easily to secondary batteries.

In addition, the electrode assembly for a secondary battery, a secondary battery including the same, and a method of manufacturing a secondary battery according to an embodiment of the present invention provide a self-pressing member with a heat-shrinkable tube that shrinks by heat, thereby using the shrinkage force of the heat-shrinkable tube to form a negative electrode. The electrode assembly body in which the anode and the separator are stacked can be pressurized to a preset pressure, and as a result, the electrode assembly is prepressurized to the set pressure to stably maintain the gap between the cathode and the anode even when gas is generated inside the secondary battery. You can. Therefore, in this embodiment, even if gas is generated inside the secondary battery when used, the gap between the negative electrode and the positive electrode is not increased by the gas, so the internal resistance of the secondary battery increases due to the increase in the gap between the negative electrode and the positive electrode in the existing secondary battery. Accordingly, the problem of blocking the flow of current can be prevented in advance.

In addition, the electrode assembly for a secondary battery according to an embodiment of the present invention, a secondary battery including the same, and a method of manufacturing a secondary battery include applying a heat shrinkable tube, which is a self-pressing member, to the electrode assembly body, and then applying heat to the heat shrinkable tube. Since the electrode assembly is manufactured using a simple method, the electrode assembly to which the self-pressing member is applied can be easily manufactured at a low cost, and the work process for applying the self-pressing member is quick and simple, thereby increasing the manufacturing efficiency of secondary batteries.

1 is a diagram schematically showing an electrode assembly for a secondary battery according to an embodiment of the present invention.
Figure 2 is a diagram schematically showing a method of manufacturing a secondary battery including an electrode assembly according to an embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited or limited by the examples. The same reference numerals in each drawing indicate the same members.

Figure 1 is a diagram schematically showing an electrode assembly 100 for a secondary battery according to an embodiment of the present invention.

A secondary battery (not shown) according to an embodiment of the present invention may include an electrode assembly 100, a case (not shown), and an electrolyte (not shown).

Here, the electrode assembly 100 is a component in which electricity is charged or discharged, and may be formed by alternately stacking a plurality of cathodes 112, anodes 114, and separators 116. The planar shape of the electrode assembly 100 as described above is generally formed as a rectangular structure, but it is not limited thereto and may be formed as a planar structure of various shapes such as a circle, oval, or pentagon. The detailed configuration of the electrode assembly 100 of this embodiment will be described again below.

Also, the case can accommodate the electrode assembly 100 therein. The case as described above may be formed in a can or pouch shape. A storage space larger than the electrode assembly 100 may be formed inside the case, and the electrode assembly 100 may be stored in the storage space.

Additionally, electrolyte solution (not shown) may be injected into the storage space of the case storing the electrode assembly 100. At this time, it is desirable that the case be provided with a structure that does not leak electrolyte.

Meanwhile, in this embodiment, for convenience of explanation, the secondary battery is described as a lithium-ion secondary battery. However, since the separator, case, and electrolyte that constitute the secondary battery are not closely related to the technical idea of the present invention, the separator, case, and electrolyte are not closely related to the technical idea of the present invention. A detailed description of the electrolyte will be omitted.

Hereinafter, the electrode assembly 100 of the present invention will be described in detail with reference to FIG. 1.

Referring to FIG. 1, the electrode assembly 100 for a secondary battery according to an embodiment of the present invention includes an electrode assembly body 110 consisting of a cathode 112, an anode 114, and a separator 116, and an electrode assembly body. It may include a self-pressing member 120 that presses 110 to a preset pressure.

The electrode assembly main body 110 has a structure in which a cathode 112, an anode 114, and a separator 116 are stacked vertically, and a plurality of cathodes 112 and a plurality of anodes 114 can be alternately stacked. there is. For example, the electrode assembly main body 110 includes a plurality of stacked cathodes 112, anodes 114 stacked so as to be respectively disposed between the cathodes 112, and between the anodes 114 and the cathodes 112. It may include a separator 116 disposed in each.

Here, the anode 114 and the cathode 112 may be formed in a thin sheet shape, and a plurality of the anode 114 and the cathode 112 may be stacked alternately from the bottom to the top of the electrode assembly 100. The number of stacks of the positive electrode 114 and the negative electrode 112 as described above can be appropriately determined depending on the design conditions and performance requirements of the secondary battery. Hereinafter, in this embodiment, for convenience of explanation of the electrode assembly 100, the electrode assembly 100 will be described as having a stacked structure of three cathodes 112 and two anodes 114, but is limited thereto. However, the number of stacks of the anode 114 and the cathode 112 can be varied.

Additionally, the negative electrode tab 113 may protrude from one side of the negative electrode 112, and the positive electrode tab 115 may protrude from one side of the positive electrode 114. The negative electrode tabs 113 of the negative electrodes 112 may be gathered together and connected to the negative terminal of the secondary battery, and the positive electrode tabs 115 of the positive electrodes 114 may be gathered together and connected to the positive terminal of the secondary battery.

In addition, the separator 116 is provided in a thin sheet shape like the cathode 112 and the anode 114, but is disposed one by one between the cathode 112 and the anode 114, or is formed between the cathode 112 and the anode ( 114), singular pieces may be arranged in a zigzag shape. Hereinafter, for convenience of explanation, this embodiment will describe that a single separator 116 is disposed between the cathodes 112 and the anodes 114.

The self-pressing member 120 may be disposed in a structure surrounding the outer portion of the electrode assembly body 110 to press the electrode assembly body 110 to a preset pressure. The pressure of the self-pressing member 120 as described above can prevent a gap from occurring between the cathode 112 and the anode 114 due to gas generated inside the secondary battery when the secondary battery is used. .

For example, the self-pressing member 120 may be provided as a heat shrinkable tube 120 that shrinks by heat. However, it is not limited to this, and the self-pressing member 120 may be formed of various materials and shapes depending on the design conditions and circumstances of the secondary battery. For example, the self-pressing member 120 is an elastic body mounted on the electrode assembly body 110 with a preset elastic force, a tape member taped to the electrode assembly body 110 with a preset bonding force, or an electrode assembly body ( 110) may be formed of a wire, etc.

The heat shrinkable tube 120 of this embodiment may be made of a material that shrinks and deforms when heat is applied. Therefore, while the electrode assembly main body 110 is placed inside the heat shrinkable tube 120, heat can be applied to the heat shrinkable tube 120 to shrink it, thereby causing the heat shrinkable tube 120 to form the electrode assembly main body ( 110) can be pressed and fixed to the outer part with a predetermined pressure. That is, the electrode assembly body 110 may be arranged to be accommodated inside the heat shrinkable tube 120, and the heat shrinkable tube 120 may be applied by heat to press the outer surface of the electrode assembly body 110 to a preset pressure. The amount of heat shrinkage can be adjusted.

Here, the self-pressing member 120 may be provided to press the electrode assembly body 110 along the stacking direction of the cathode 112, the anode 114, and the separator 116. Therefore, even if gas is generated inside the secondary battery when the secondary battery is used, the gap between the negative electrode 112 and the positive electrode 114 due to the pressure of the self-pressing member 120 can be prevented in advance. As described above, if a gap is not formed between the negative electrode 112 and the positive electrode 114 due to the pressure of the self-pressing member 120, the gap formed between the negative electrode 112 and the positive electrode 114 causes the inside of the secondary battery to It is possible to prevent the problem of the current flow in the secondary battery being blocked due to a significant increase in resistance.

Meanwhile, the self-pressing member 120 may be provided with an opening 122 through which the negative electrode tab 113 and the positive electrode tab 115 are disposed. Therefore, the negative electrode tab 113 and the positive tab 115 are positioned in the opening 122 of the self-pressing member 120 before pressing and fixing the self-pressing member 120 to the outer surface of the electrode assembly main body 110. It is desirable.

The openings 122 as described above may be formed on both sides of the self-pressing member 120 with a size sufficient to allow the negative electrode tab 113 and the positive electrode tab 115 to pass through. Hereinafter, in this embodiment, the self-pressing member 120 is provided with a heat shrinkable tube 120, and the heat shrinkable tube 120 is described as being formed in a cylindrical shape with openings 122 formed on both sides.

For reference, the self-pressing member 120 may be formed with a plurality of through holes for the electrolyte to pass through under the premise that the pressure applied to the electrode assembly main body 110 is provided at a preset size.

Figure 2 is a diagram schematically showing a method of manufacturing a secondary battery including an electrode assembly 100 according to an embodiment of the present invention.

The manufacturing method of a secondary battery including the electrode assembly 100 according to an embodiment of the present invention configured as described above is as follows.

Referring to FIG. 2, the method of manufacturing a secondary battery according to an embodiment of the present invention includes the step (S1) of preparing an electrode assembly body 110 by stacking a cathode 112, an anode 114, and a separator 116. Reference), completing the electrode assembly 100 by applying the self-pressing member 120 to the electrode assembly body 110 (see S2), storing the electrode assembly 100 inside the case (see S3) , and a step of injecting an electrolyte into the interior of the case (see S4).

In the step of preparing the electrode assembly main body 110 (see S1), the cathode 112, the anode 114, and the separator 116 may be stacked alternately in the vertical direction. As shown in FIG. 1, the electrode assembly main body 110 of this embodiment includes a separator 116, a cathode 112, a separator 116, an anode 114, a separator 116, and a cathode ( 112), the separator 116, the anode 114, the separator 116, the cathode 112, and the separator 116 may be laminated in that order.

In the step of completing the electrode assembly 100 (see S2), the electrode assembly 100 can be completed by applying the self-pressing member 120 to the electrode assembly main body 110. At this time, the self-pressing member 120 may be provided as a heat shrinkable tube 120 made of a material that shrinks by heat.

For example, the step of completing the electrode assembly 100 includes placing the electrode assembly body 110 inside the heat shrink tube 120, applying heat to the heat shrink tube 120, and forming the heat shrink tube 120. ), and removing the heat applied to the heat shrinkable tube 120 when the heat shrinkable tube 120 is pressed to the outer surface of the electrode assembly main body 110 at a preset pressure. .

Here, in this embodiment, by adjusting the size and time of heat applied to the heat shrinkable tube 120, the amount of heat shrinkage of the heat shrinkable tube 120 can be adjusted, and by adjusting the amount of heat shrinkable amount of the heat shrinkable tube 120, the electrode The amount of pressure applied to the assembly body 110 can be appropriately set and changed.

Meanwhile, in the step of disposing the electrode assembly body 110, the cathode tab 113 of the cathode 112 and the anode tab 115 of the anode 114 are penetrated through the opening 122 formed in the heat shrinkable tube 120. It can be arranged properly. By doing so, it is possible to prevent the heat shrinkable tube 120 from interfering with the negative electrode tab 113 or the positive electrode tab 115 during the step of heat shrinking the heat shrinkable tube 120.

In the step of storing the electrode assembly 100 in the case (see S3), the electrode assembly 100, which has a structure in which the self-pressing member 120 is heat-shrinked and pressed to the outer part of the electrode assembly main body 110, is formed into one part. It can be handled and placed in a storage space formed inside the case.

In the step of injecting the electrolyte into the case (see S4), the electrolyte is injected into the internal space of the case so that the electrode assembly 100 is sufficiently supported by the electrolyte inside the case.

Accordingly, the method of manufacturing a secondary battery according to this embodiment is structured to press the electrode assembly body 110 by itself using the self-pressing member 120, so that the electrode assembly 100 is pressed into the inside of the case. There is no need to install a separate structure, and it can have advantages over existing secondary batteries that install a separate structure in terms of manufacturing convenience, productivity, and price competitiveness.

As described above, the embodiments of the present invention have been described with specific details such as specific components and limited examples and drawings, but this is only provided to facilitate a more general understanding of the present invention, and the present invention is limited to the above embodiments. This does not mean that various modifications and variations can be made from this description by those skilled in the art. Accordingly, the spirit of the present invention should not be limited to the described embodiments, and all claims that are equivalent or equivalent to the claims as well as the following claims fall within the scope of the present invention.

100: Electrode assembly for secondary battery
110: Electrode assembly body
112: cathode
113: cathode tab
114: anode
115: anode tab
116: Separator
120: Self-pressing member (heat shrink tube)

Claims (8)

An electrode assembly body in which a cathode, an anode, and a separator are stacked; and
a self-pressing member disposed in a structure surrounding the outer portion of the electrode assembly body to press the electrode assembly body to a preset pressure;
An electrode assembly for a secondary battery comprising a.
According to paragraph 1,
The self-pressing member is provided as a heat shrinkable tube that shrinks by heat,
The electrode assembly body is disposed to be accommodated inside the heat shrinkable tube, and the heat shrinkable tube is heat-shrinked to press the outer surface of the electrode assembly body at a preset pressure.
According to paragraph 1,
The electrode assembly body,
A plurality of cathodes are stacked;
An anode stacked so as to be disposed between the cathodes, respectively; and
It includes a separator disposed between the anode and the cathode, respectively,
An electrode assembly for a secondary battery, wherein the self-pressing member presses the electrode assembly body with a preset pressure along a stacking direction of the cathode, the anode, and the separator.
According to paragraph 3,
A negative electrode tab protrudes on one side of the cathode, and a positive electrode tab protrudes on one side of the positive electrode,
An electrode assembly for a secondary battery, characterized in that the self-pressing member is provided with an opening through which the negative electrode tab and the positive electrode tab are disposed.
The electrode assembly according to any one of claims 1 to 4;
a case in which the electrode assembly is stored; and
Electrolyte solution injected into the interior of the case;
A secondary battery containing.
Preparing an electrode assembly body by stacking a cathode, an anode, and a separator;
Completing the electrode assembly by applying a self-pressing member to the electrode assembly body;
Storing the electrode assembly inside a case; and
Injecting an electrolyte into the case;
A method of manufacturing a secondary battery comprising.
According to clause 6,
The self-pressing member is provided as a heat shrinkable tube that shrinks by heat,
The step of completing the electrode assembly is,
Placing the electrode assembly body inside the heat shrink tube;
heat shrinking the heat shrinkable tube by applying heat to the heat shrinkable tube; and
A method of manufacturing a secondary battery comprising: removing heat applied to the heat shrinkable tube when the heat shrinkable tube is pressed to an outer surface of the electrode assembly body at a preset pressure.
In clause 7,
In the step of placing the electrode assembly body,
A method of manufacturing a secondary battery, characterized in that the negative electrode tab protruding on one side of the negative electrode and the positive electrode tab protruding on one side of the positive electrode are disposed to penetrate the opening formed in the heat shrinkable tube so as not to interfere with the heat shrinkable tube.

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