KR20220112515A - Method for manufacturing electrode assembly including line compression and surface compression, electrode assembly manufactured using the same - Google Patents

Abstract

The present invention relates to a method for manufacturing an electrode assembly, an electrode assembly manufactured using the same, and a secondary battery comprising the electrode assembly. More specifically, the method comprises: (s1) sequentially disposing a separator and a first electrode; (s2) a line-compression step of disposing a separator on an upper surface of the first electrode, and rolling and compressing the separator from one end to the other end of the upper surface using a compression roller; (s3) disposing a second electrode on an upper surface of the separator; (s4) a line-compression step of disposing a separator on an upper surface of the second electrode, and rolling and compressing the separator from one end of an upper surface to the other end using a compression roller; and (s5) a surface compression step of compressing the electrode assembly manufactured in steps (s1) to (s4) using a compression plate.

Description

Method for manufacturing electrode assembly including line compression and surface compression, electrode assembly manufactured using the same}

The present invention relates to a method for manufacturing an electrode assembly including line compression bonding and surface compression bonding, and an electrode assembly manufactured using the same. Specifically, the upper surface of the separator disposed on the top of the electrode is pressed while rolling with a compression roller, and the laminate of the electrode and the separator is pressed using a pair of compression plates to strengthen the bonding force between the electrode and the separator. It relates to an electrode assembly manufacturing method comprising a, and an electrode assembly manufactured using the same.

As the demand for mobile devices such as smartphones increases, the demand for secondary batteries used as their energy sources is increasing. Secondary batteries are also being applied to electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), and energy storage devices (ESSs).

On the other hand, the secondary battery can be classified into a cylindrical battery, a prismatic battery, a pouch-type battery, etc. according to the shape. Among them, a pouch-type battery that can be stacked with a high degree of integration, has a high energy density per weight, and is easily deformable in shape, is attracting a lot of attention. The pouch-type battery means a battery in which the battery case is made of a laminate sheet, and has a structure in which an electrode assembly is built into the battery case.

The electrode assembly of the anode/separator/cathode structure constituting the secondary battery is largely divided into a jelly-roll type (winding type), a stack type (laminated type), and a stack-folding type according to its structure. The jelly-roll type electrode assembly is formed by coating an electrode active material on a metal foil used as a current collector, drying and pressing, cutting it into a band of a desired width and length, and separating the negative electrode and the positive electrode using a separator, and then spiral manufactured by winding The jelly-roll type electrode assembly is suitable for a cylindrical battery, but has disadvantages such as a peeling problem of the electrode active material and low space utilization when applied to a prismatic or pouch type battery. On the other hand, the stacked electrode assembly has a structure in which a plurality of positive and negative electrode units are sequentially stacked, and has an advantage in that it is easy to obtain a prismatic shape. The stack-folding type is an electrode assembly having an advanced structure that is a mixture of the jelly-roll type and the stack type, and is a full cell or positive electrode (cathode)/separator/negative electrode having a basic structure of a positive electrode/separator/negative electrode of a certain unit size. (Anode)/Separator/Anode (Cathode) This is a structure in which a bicell with a basic structure is folded using a long continuous separator film.

As shown in FIG. 1 , the stacked electrode assembly according to the prior art is obtained by sequentially stacking a separator 103 / a first electrode 101 / a separator 103 / a second electrode 102 / a separator 103 . Then, it is compressed using a pressing plate.

In addition, as shown in FIG. 2, in the stack-folding type electrode assembly according to the prior art, the first electrode 201 and the second electrode 202 are stacked while the separator 203 is bent in a zigzag manner, and the electrode assembly is manufactured. . In the manufacturing process, the tension roller 240 is disposed in consideration of the direction of movement of the bending unit 230, and the mandrel 220 disposed on the upper surface of the outer side of one side of the electrode fixes the separator while the tension of the separator 203 is lowered. prevent that

The conventional techniques as described above have a problem in that it is difficult to provide sufficient adhesion between the separator and the electrodes, and thus the thickness of the electrode assembly is increased.

Therefore, in the development of a pouch-type secondary battery, the compatibility of the separator and the electrode and the thickness of the electrode assembly are essential considerations.

Patent Document 1 includes a separator supply device, a heating unit for heating the separator supplied by the separator supply device, an electrode supply device, and a matching device for matching the electrode supplied by the electrode supply device and the separator heated by the heating unit A lamination apparatus for secondary batteries was disclosed. Patent Document 1 discloses a lamination technology including a heating part for heating a separator to match the electrode, but the separator provided between the positive electrode and the negative electrode to be bonded in the lamination process is tilted to one side, resulting in a short circuit between the two poles, resulting in overheating and a battery fire Are there any problems with accidents?

As such, an effective technique for improving the bonding strength between the separator and the electrode in the electrode assembly manufacturing process has not been proposed yet.

Republic of Korea Patent Publication No. 2019-0056812 ('Patent Document 1')

The present invention is to solve the above problems, and uses a pressing roller and a pressing plate to improve adhesion between a separator and an electrode facing each other in the process of manufacturing a stacked electrode assembly or/and a stack-laminated electrode assembly An object of the present invention is to provide an electrode assembly manufacturing apparatus and an electrode assembly manufactured using the same.

In the present invention for achieving the above object, (s1) sequentially disposing a separator and a first electrode, (s2) placing a separator on the upper surface of the first electrode, and at one end of the upper surface of the separator A pre-compression step of pressing while rolling using a compression roller to the other end, (s3) disposing a second electrode on the upper surface of the separator, (s4) disposing a separator on the upper surface of the second electrode, and the separator A pre-compression step of pressing while rolling from one end to the other end of the top surface of the It is possible to provide a method for manufacturing an electrode assembly comprising.

In the electrode assembly manufacturing method according to the present invention, the electrode assembly may be a stacked electrode assembly.

In addition, in the electrode assembly manufacturing method according to the present invention, one or more pressing rollers may be used in the (s2) and/or (s4) steps.

In addition, in the electrode assembly manufacturing method according to the present invention, the electrode assembly may be a stack-folding type electrode assembly.

In addition, in the electrode assembly manufacturing method according to the present invention, between the (s2) and (s3) steps, the step of folding the separator using a pressing roller as a support shaft may be included.

is an electrode assembly manufacturing method.

In addition, in the electrode assembly manufacturing method according to the present invention, between the steps (s3) and (s4), after pulling out the compression roller between the separators, a tension step of pulling the folded upper separator in the folding direction is included. A method for manufacturing an electrode assembly.

In addition, in the electrode assembly manufacturing method according to the present invention, after performing the step (s2), it may include the step of pressing using a pressing plate.

In addition, in the electrode assembly manufacturing method according to the present invention, the temperature, pressure, and rolling speed of the compression roller may be adjusted by a control unit.

In addition, in the electrode assembly manufacturing method according to the present invention, the separator may be coated with a coating material having an adhesive force on the surface.

The present invention provides an electrode assembly produced according to the electrode assembly manufacturing method, and also provides a secondary battery including the electrode assembly and a battery module including the secondary battery.

The present invention can also be provided in the form of various combinations of means for solving the above problems.

As described above, the electrode assembly manufacturing method according to the present invention can improve the adhesion between the facing electrode and the separator by using a method using a line compression bonding and a surface compression bonding.

A bar supporting the folding position of the separation membrane by using a pressing roller is advantageous in preventing wrinkling of the folded separation membrane.

In addition, by improving the adhesion between the facing electrode and the separator, it is possible to reduce the stacking thickness of the electrode assembly formed by stacking the electrodes and the separator.

As described above, according to the present invention, since an electrode assembly having a reduced thickness can be manufactured, the energy density of a secondary battery and a battery module using the electrode assembly can be improved.

1 is a schematic diagram of a manufacturing process of a stacked electrode assembly according to the prior art.
2 is a stack according to the prior art - a schematic diagram of a manufacturing process of a folding type electrode assembly.
3 is a schematic diagram of a manufacturing process of a stacked electrode assembly according to a first embodiment of the present invention.
4 to 8 are stacks according to a second embodiment of the present invention - a schematic diagram of a manufacturing process of a folding type electrode assembly.
9 is a schematic diagram of a method for measuring wet adhesion between an electrode and a separator.
10 is a view showing the measurement result of wet adhesion between the electrode and the separator.

Hereinafter, embodiments in which those of ordinary skill in the art to which the present invention pertains can easily practice the present invention will be described in detail with reference to the accompanying drawings. However, when it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention in describing the operating principle of the preferred embodiment of the present invention in detail, the detailed description thereof will be omitted.

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

In addition, descriptions that limit or add elements are applicable to all inventions unless there are special limitations, and are not limited to descriptions of specific inventions.

Also, throughout the description and claims of the present application, the singular includes the plural unless otherwise indicated.

Also, throughout the description and claims herein, "or" is intended to include "and" unless stated otherwise. Therefore, "comprising A or B" means all three cases including A, including B, or including A and B.

Hereinafter, a method for manufacturing an electrode assembly according to the present invention will be described with reference to the accompanying drawings.

3 is a schematic diagram of a manufacturing process of a stacked electrode assembly according to a first embodiment of the present invention.

Referring to FIG. 3 , a method for manufacturing a stacked electrode assembly according to a first embodiment of the present invention is as follows. As shown in FIG. 3 ( c1 ), a first layer separator 1103 , a first electrode 1101 . ) and a second layer separator 1103 are sequentially stacked on the upper surface of the lower compression plate 1111 . Next, the pressure is applied while rolling from one edge to the other edge of the top surface of the second layer separation membrane 1103 located at the top using the compression roller 1120 to the left in the x-axis direction. In addition, one or more compression rollers 1120 may be provided to pressurize while continuously rolling.

The compression roller 1120 may pressurize while rolling the upper surface of the second layer separation membrane 1103 located at the top at a pressure of 50-100 kgf/cm ² . When pressurized with a pressure less than 50 kgf/cm ² , the separator 1103 and the first electrode 1101 do not adhere to each other, or may be easily separated even if they are adhered, and when pressurized with a pressure greater than 100 kgf/cm ² , the separator 1103 and / Or the electrode (the first electrode or the second electrode to be described later) may be damaged, which is not preferable.

In addition, the compression roller 1120 may pressurize while rolling the upper surface of the second layer separation membrane 1103 located at the top in a state heated to a temperature of 80 to 100 ℃. When pressurized at a temperature lower than 80 ° C., the separator 1103 and the first electrode 1101 do not adhere to each other or are easily detached even if they are adhered. This is not preferable because it may cause clogging or deformation of the separator 1103 and/or the electrode (the first electrode or the second electrode to be described later).

After pressing the uppermost second layer separation film 1103 with the compression roller 1120 is completed, the uppermost second layer separation film 1103 may be pressed using the upper compression plate 1112 . In this case, the lower compression plate 1111 may press the lower surface of the first layer separation film 1103 located thereon upward in the direction of the first electrode 1101 . This is advantageous in improving the adhesion of the first layer separator 1103 positioned to face the lower surface of the first electrode 1101 .

In addition, the upper compression plate 1111 and the lower compression plate 1112 may be heated to a temperature of 80 to 100 °C, and pressurized to a pressure of 50 to 100 kgf/cm ² . Since the temperature and pressure conditions are described in the description of the compression roller 1120 , they are omitted.

Subsequently, as shown in (c2) of FIG. 3, after pressing with a compression roller 1120, the second electrode 1102 and the third layer separation membrane 1103 are sequentially applied to the upper surface of the second layer separation membrane 1103. additionally laminated with Next, the upper surface of the third layer separation membrane 1103 is pressed while rolling rightward in the x-axis direction from one end of the edge of the separation membrane to the other end facing it using one or more compression rollers 1120 .

Next, as shown in (c3) of FIG. 3, the stacked first layer separator 1103, first electrode 1101, second layer separator 1103, second electrode 1102, and third layer separator ( 1103) is pressed using the upper compression plate 1112 and/or the lower compression plate 1111 to complete the electrode assembly basic unit.

In the present invention, the temperature, pressure, and rolling speed of the compression roller 1120, and the temperature, pressure, and pressing speed of the upper compression plate 1112 and the lower compression plate 1111 are controlled by a separately provided control unit (not shown). do.

The first electrode may be an anode, the second electrode may be a cathode, or vice versa.

In the first embodiment of the present invention, the electrode assembly basic unit composed of separator/first electrode/separator/second electrode/separator has been described, but anode/separator/cathode and anode/separator/cathode/separator/anode/separator/ It may be a full cell with a negative electrode structure or a bi-cell structure with a unit structure of positive electrode / separator / negative electrode / separator / positive electrode and a unit structure of negative electrode / separator / positive electrode / separator / negative electrode, the full cell and It may be an electrode assembly in which bicells are combined with a separator interposed therebetween.

4 to 8 are stacks according to a second embodiment of the present invention - a schematic diagram of a manufacturing process of a folding type electrode assembly.

4 to 8, in the present invention, the stack-folding type electrode assembly manufacturing method is as described below.

As shown in FIG. 4 , after the separator 1203 in the form of a long sheet is flatly disposed on the upper surface of the lower compression plate 1211 , the first electrode 1201 is positioned on the upper surface of the separator 1203 . Then, the long sheet-shaped separator 1230 is folded so as to cover the upper surface of the first electrode 1201 while surrounding the side surface of the first electrode 1201 . A separator tension member ( not shown) may be provided. Of course, it is obvious that deformation or movement of the separator 1203 positioned between the first electrode 1201 and the lower compression plate 1211 does not occur.

Then, starting from the edge side where the first electrode 1201 contacts the side surface of the first electrode 1201 wrapped with the separator 1203 using the compression roller 1220, rolling to the other end edge facing the edge while rolling The upper surface of the separation membrane 1203 is pressed to the left in the x-axis direction.

Next, as shown in FIG. 5 , after pressing the upper surface of the separator 1203 folded on the upper surface of the first electrode 1201 using a compression roller 1220, the second electrode 1202 is disposed on the upper surface of the pressurized separation membrane 1203 .

Next, as shown in FIG. 6 , the long sheet-shaped separator 1203 is folded to the right in the x-axis direction using the compression roller 1220 as a support, and the compression roller 1220 is placed between the folded separation membranes. take it out Next, the separator 1203 folded on the top surface of the second electrode 1202 is pulled to the right in the x-axis direction using a tension member (not shown) that pulls to cover the top surface of the second electrode 1202 . After that, keep the tension.

Then, as shown in FIG. 7 , the upper surface of the separator 1203 covering the upper surface of the second electrode 1202 is pressed while rolling to the right in the x-axis direction using the compression roller 1220 . The compression roller 1220 starts from the edge side of the second electrode 1202 in which the separator 1203 is folded and moves while rolling to the other side facing it.

Then, as shown in FIG. 8 , after completion of pressing while rolling the upper portion of the separator 1203 positioned on the upper surface of the second electrode 1202 by the compression roller 1202 , the upper compression plate 1212 and After the separator 1203 folded between the lower compression plates 1211 and the first electrode 1201 and the second electrode 1202 positioned therebetween are positioned, opposing pressing may be performed. Here, the first electrode 1201 and the second electrode 1202 may be alternately disposed between the folded separator 1203, and the number thereof is not particularly limited.

In the stack-folding type electrode assembly manufacturing method according to the present invention, the operating temperature, pressure, and rolling speed of the compression roller 1220, and the operating temperature, pressure and pressing speed of the upper compression plate 1202 and the lower compression plate 1201 are the above It is omitted because it is the same as the manufacturing method of the stacked electrode assembly.

The present invention provides a stack-type electrode assembly or a stack-folding-type electrode assembly using the electrode assembly manufacturing method.

A stack-type electrode assembly or a stack-type electrode assembly manufactured using the method for manufacturing an electrode assembly according to the present invention provides a secondary battery and a battery module including the folding-type electrode assembly. The secondary battery and the battery module are heated and pressed by a pressing roller and a pair of pressing plates, so that the adhesion between the electrode and the separator is improved and the energy density can be improved by including an electrode assembly in which the thickness of the electrode and the separator laminate is reduced. .

Hereinafter, the content of the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited thereto.

Example 1

A negative electrode is disposed on the upper side of the lower compression plate, and a separator is disposed on the top of the negative electrode, and the upper end of the separator is pressed while rolling using a compression roller. Then, after placing the pressurized negative electrode and the separator laminate between the upper pressing plate and the lower pressing plate, the negative electrode and the separator pressed by a pressing roller centered in the opposite direction between the upper pressing plate and the lower pressing plate Pressurized again to prepare a negative electrode and a separator laminate.

Example 2

It is the same as Example 1 except for using an anode instead of a cathode.

Comparative Example 1

A negative electrode is disposed on the upper side of the lower compression plate, a separator is disposed on the top of the negative electrode, and then the negative electrode is disposed between the upper compression plate and the lower compression plate. Then, the negative electrode and the separator positioned in the center of the upper compression plate and the lower compression plate in opposite directions were pressed again to prepare a negative electrode and a separator laminate.

Comparative Example 2

It is the same as in Comparative Example 1 except for using a positive electrode instead of a negative electrode.

Method of measuring wet adhesion between electrode and separator

As shown in FIG. 9 , the electrode, separator, and electrolyte are accommodated in a pouch, and then the wet adhesion between the electrode and the separator is measured using the electrode and separator stack after the pouch is removed. After bonding the electrode and the separator positioned at the top of the separator with a tape that can serve as a connection part, the tape is fixed to the UTM equipment, and the measured adhesive strength value is recorded. When measuring the adhesive force between the negative electrode and the separator, the negative electrode is located at the lower end of the separator that is pulled off (c), and when measuring the adhesive force between the positive electrode and the separator, the positive electrode is located at the lower end of the separator (d).

According to the measurement conditions (speed, distance) set in the UTM equipment, the adhesion between the electrode and the separator (adhesion strength = adhesion strength) is recorded on the UTM equipment. In the present invention, the UTM equipment was used as a universal Test Machine LS1 model instrument manufactured by AMETEK.

As shown in FIG. 10, the adhesive force between the negative electrode and the separator according to the linear compression and surface compression according to the present invention is about 24 times the adhesive force between the negative electrode and the separator using only the surface compression, and the linear compression and surface compression according to the present invention. The adhesive force between the weak electrode and the separator according to the method was found to be about 4 times that of the weak electrode and the separator using only surface compression.

As described above in detail a specific part of the content of the present invention, for those of ordinary skill in the art, these specific descriptions are only preferred embodiments, and the scope of the present invention is not limited thereby, It is obvious to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention, and it is natural that such variations and modifications fall within the scope of the appended claims.

100: Stacked electrode assembly manufacturing process according to the prior art
101, 201: first electrode
102, 202: second electrode
103, 203, 1103, 1203: separator
110: crimp plate
200: stack / folding type electrode assembly manufacturing process according to the prior art
220: mandrel
230: bending unit
231: guide roller
232: tension roller
240: separator supply unit
1101, 1201: first electrode
1102, 1202: second electrode
1110, 1210: press plate
1111, 1211: base plate
1112, 1212: upper compression plate
1120, 1220: heating pressing roller

Claims (12)

(s1) sequentially disposing a separator and a first electrode;
(s2) a pre-compression bonding step of arranging a separator on an upper surface of the first electrode, and rolling from one end to the other end of the upper surface of the separator using a compression roller;
(s3) disposing a second electrode on the upper surface of the separator;
(s4) a pre-compression bonding step of arranging a separator on an upper surface of the second electrode and pressing while rolling using a compression roller from one end of the upper surface of the separator to the other end; and
(s5) a surface compression step of pressing the electrode assembly prepared in the steps (s1) to (s4) using a compression plate; According to claim 1,
The electrode assembly is a method of manufacturing an electrode assembly that is a stacked electrode assembly. 3. The method of claim 2,
An electrode assembly manufacturing method using one or more compression rollers in the step (s2) and/or step (s4). According to claim 1,
The electrode assembly is a stack-folding electrode assembly method of manufacturing an electrode assembly. 5. The method of claim 4,
Between the step (s2) and the step (s3), the electrode assembly manufacturing method comprising the step of folding the separator using a pressing roller as a support shaft. 6. The method of claim 5,
Between the steps (s3) and (s4), after pulling out the compression roller between the separators, the method of manufacturing an electrode assembly comprising a tension step of pulling the folded upper separator in the folding direction. The method of claim 1,
After performing the step (s2),
An electrode assembly manufacturing method comprising the step of pressing using a pressing plate. According to claim 1,
An electrode assembly manufacturing method in which the temperature, pressure and rolling speed of the compression roller are controlled by a control unit. According to claim 1,
The separator is an electrode assembly manufacturing method in which a coating material having an adhesive force is coated on the surface. An electrode assembly produced according to the method for manufacturing an electrode assembly according to any one of claims 1 to 9. A secondary battery comprising the electrode assembly according to claim 10. A battery module comprising the secondary battery according to claim 11 .

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