KR20180060821A - Method for manufacturing battery cell and battery using the methor - Google Patents

Abstract

Disclosed is a battery cell production method. According to one embodiment of the present invention, the battery cell production method comprises the following steps: (a) transferring a pouch case activated by charge/discharge after packaging of an electrode assembly to a processing chamber; (b) discharging gas generated in the pouch case inside the processing chamber; (c) primarily sealing the gas-released pouch case in the processing chamber; (d) cutting the primarily sealed pouch case out of the processing chamber; and (e) secondarily sealing the pouch case on the outside of the processing chamber.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery cell manufacturing method and a battery cell produced by the manufacturing method,

The present invention relates to a battery cell manufactured by a method of manufacturing a battery cell and a battery cell produced by the manufacturing method. More particularly, the present invention relates to a battery cell produced by a method of manufacturing a battery cell, And more particularly, to a battery cell manufactured by the method and a battery cell produced by the method.

2. Description of the Related Art [0002] As technology development and demand for mobile devices have increased, demand for secondary batteries as energy sources has been rapidly increasing. Conventionally, nickel-cadmium batteries or hydrogen ion batteries have been used as secondary batteries. However, The lithium secondary battery is free from charge and discharge, has a very low self-discharge rate, and has a high energy density.

These lithium secondary batteries mainly use a lithium-based oxide and a carbonaceous material as a cathode active material and an anode active material, respectively. The lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate each coated with such a positive electrode active material and a negative electrode active material are disposed with a separator interposed therebetween, and an outer casing, that is, a battery case, for sealingly storing the electrode assembly together with the electrolyte solution.

The lithium secondary battery is composed of a positive electrode, a negative electrode, a separator interposed therebetween, and an electrolyte. Depending on the type of the positive electrode active material and the negative electrode active material, a lithium ion battery (LIB), a lithium polymer battery , And PLIB). Typically, the electrodes of these lithium secondary batteries are formed by applying a positive electrode or a negative electrode active material to a current collector such as aluminum, copper sheet, mesh, film, or foil, followed by drying. Here, the secondary battery can be classified into a can type and a pouch type depending on the type of the exterior material.

The production of a battery cell of the conventional pouch type will be described with reference to the drawings. FIG. 1 is a flow chart of a conventional method of manufacturing a battery cell, and FIGS. 2 (a) and 2 (b) are views showing a manufacturing process of a conventional battery cell.

The manufacturing of the pouch-type battery cell includes a degassing process for removing gas generated inside the pouch case 2. After packaging, the activated battery cell 1 is transferred to a vacuum process chamber, where the degassing process takes place in a process chamber in which the interior is vacuum. When the gas in the pouch case 2 is exhausted from the inside of the process chamber, the pouch case 2 is sealed along the main sealing line 3 inside the vacuum process chamber as shown in Fig. 2 (a) The pouch case 2 is cut along the cutting line 4 outside the main sealing line 3 as shown in Fig. 2 (b) (S20 in Fig. 1).

However, when the degassing process is completed in the vacuum chamber, and the mail-sealed pouch case 2 is transferred to the atmospheric pressure outside the process chamber, the pressure inside the pouch case 2 and the pressure inside the pouch case 2 There is a problem that the pouch case 2 is wrinkled due to the pressure difference at atmospheric pressure and the defective insulation resistance ratio is high due to the wrinkles of the pouch case 2.

Korean Patent Laid-Open Publication No. 10-2014-0036437 (published on Mar. 26, 2014)

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a battery cell manufacturing method capable of preventing wrinkles from being generated in a pouch case and a battery cell produced by the manufacturing method.

Another object of the present invention is to provide a method of manufacturing a battery cell and a battery cell produced by the method, which can prevent the occurrence of wrinkles in the pouch case to prevent the insulation resistance failure of the battery cell and improve the insulation voltage.

The present invention also provides a method of manufacturing a battery cell that facilitates quality control of a pouch case sealing portion and a battery cell produced by the method.

According to an aspect of the present invention, there is provided a method of manufacturing an electrode assembly, comprising: (a) transferring a pouch case activated by charge / discharge after packaging of an electrode assembly to a process chamber; (b) discharging gas generated in the pouch case inside the process chamber; (c) sealing the pouch case from which the gas is discharged, inside the process chamber; (d) cutting the first sealed pouch case outside the process chamber; And (e) a second sealing of the pouch case outside the process chamber.

Further, the inside of the process chamber may be in a vacuum state, and the outside of the process chamber may be in an atmospheric pressure state.

In the step (b), a gas discharge part may be formed in the pouch case inside the process chamber, and gas may be discharged from the pouch case inside the process chamber.

The step (c) may be performed at a position where the position of the first sealing is spaced from the electrode assembly by a predetermined gap.

And, in the step (d), the first sealed portion of the pouch case may be cut.

Also, in the step (e), the position of the second sealing may be formed closer to the electrode assembly than the position of the first sealing with respect to the electrode assembly.

According to another aspect of the present invention, there is provided a battery module including the battery cell produced by the battery cell manufacturing method, wherein the battery cell produced by the battery cell manufacturing method described above can be provided, have.

Embodiments of the present invention have the effect of preventing wrinkles from being generated in the pouch case by preventing the occurrence of a pressure difference since the first sealing is performed inside the process chamber and the second sealing is performed outside the process chamber.

Further, it is possible to prevent wrinkles from being generated in the pouch case, thereby preventing defective insulation resistance of the battery cell and improving the insulation voltage.

In addition, quality control is performed only on the second sealing portion outside the process chamber, compared with the prior art in which quality control is performed on each of a plurality of main sealing portions in the process chamber, so that quality control of the pouch case sealing portion is facilitated.

1 is a flowchart of a conventional battery cell manufacturing method.
FIGS. 2 (a) and 2 (b) are views showing a manufacturing process of a conventional battery cell.
3 is a flowchart of a method of manufacturing a battery cell according to an embodiment of the present invention.
FIGS. 4 to 6 are views schematically showing a manufacturing process of a battery cell according to an embodiment of the present invention.
FIG. 7 (a) is an image of a pouch case manufactured by a conventional battery cell manufacturing method, and FIG. 7 (b) is an image of a pouch case manufactured by a method of manufacturing a battery cell according to an embodiment of the present invention.

Hereinafter, a battery cell manufacturing method according to a preferred embodiment of the present invention and a battery cell produced by the manufacturing method will be described in detail with reference to the accompanying drawings.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, various alternatives It is to be understood that equivalents and modifications are possible.

In the drawings, the size of each element or a specific part constituting the element is exaggerated, omitted or schematically shown for convenience and clarity of description. Therefore, the size of each component does not entirely reflect the actual size. In the following description, it is to be understood that the detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The term " bond " or " connection, " as used herein, is intended to encompass a case in which one member and another member are directly or indirectly connected, And the like.

FIG. 3 is a flowchart of a method of manufacturing a battery cell according to an embodiment of the present invention, and FIGS. 4 to 6 are views illustrating a manufacturing process of a battery cell according to an embodiment of the present invention.

The fabrication of the pouch-shaped battery cell 10 may typically consist of a packaging process, an activation process and a degassing process. In the packaging process, the electrode assembly 500 is housed in the pouch case 100, and then the electrolytic solution is injected and sealed. When the packaging process of the electrode assembly 500 is completed, the activation process of activating the battery cell 10 through charging and discharging of the battery cell 10 proceeds. When the battery cell 10 is charged and discharged, gas is generated inside the pouch case 100, and the gas generated inside the pouch case 100 is discharged to the outside of the pouch case 100 through the degassing process. Since the degassing process is performed inside the process chamber, the battery cell 10 activated by charging and discharging is transferred to the process chamber. Here, the inside of the process chamber may be a vacuum. Various methods can be used for transferring the battery cell 10.

When the battery cell 10 is transferred to the vacuum processing chamber, the gas generated in the pouch case 100 is discharged from the inside of the processing chamber. The gas generated in the pouch case 100 is supplied to the pouch case 100 through the gas in the pouch case 100 and the pressure in the vacuum inside the process chamber 100. [ The gas can be discharged to the outside of the pouch case 100 through the gas discharge portion formed in the pouch case 100 due to the difference in pressure. The gas discharge portion can be formed in various ways within the process chamber. The gas discharging part may be formed by cutting at least a part of the pouch case 100, or may be formed by punching a gas discharging hole in the pouch case 100.

Referring to FIG. 4, when the gas generated in the pouch case 100 is discharged through the gas discharging portion in the process chamber, a first sealing is performed along the first sealing line 200 in the pouch case 100 S100). Here, the first sealing of the pouch case 100 takes place inside a vacuum processing chamber. The first sealing is to seal one side of the pouch case 100 to prevent foreign matter or moisture from penetrating into the pouch case 100 through the gas discharging portion of the pouch case 100. At this time, the first sealing line 200 may be formed at a position spaced apart from the electrode assembly 500 stored in the pouch case 100 by a predetermined interval. The first sealing line 200 may be formed outside the second sealing line 400, that is, at a position farther from the electrode assembly 500, so that the first sealing line 200 may be formed on the second sealing line 400, May be formed to be spaced apart from the electrode assembly 500 in consideration of the position of the electrode assembly 400. That is, if the first sealing line 200 is formed at a position too close to the electrode assembly 500, it is not easy to form the second sealing line 400. Considering this position of the second sealing line 400 The spacing distance of the first sealing line 200 can be set.

When the first sealing is completed along the first sealing line 200 in the process chamber, the pouch case 100 is transferred to the outside of the process chamber. At this time, the outside of the process chamber is at atmospheric pressure. Here, the feeding method of the pouch case 100 may be various. 5, the first sealed pouch case 100 is cut along the cutting line 300 outside the process chamber (S200 of FIG. 3). The first sealed portion of the pouch case 100 may be cut by itself although the cutting portion of the pouch case 100 may vary. Since the first sealed portion is cut, the contaminated portion of the pouch case 100 can be removed when the electrolyte is injected. Further, since the cutting is performed outside the process chamber, the inside and the outside of the pouch case 100 Is adjusted to be the same. Thereby, a pressure difference does not occur between the inside and the outside of the pouch case 100. Although the cutting line 300 is shown in FIG. 5 as being formed on the inside of the first sealing line 200, this is only one example, and if the sealed first sealing can be opened, It is also possible to cut itself.

Referring to FIG. 6, when the pressure inside and outside of the pouch case 100 is adjusted by cutting outside the process chamber, the pouch case 100 is sealed from the outside of the process chamber (S300 in FIG. 3). Here, the position of the second sealing line 400 may be formed closer to the electrode assembly 500 than the position of the first sealing line 200 with respect to the electrode assembly 500. Although both the first sealing line 200 and the second sealing line 400 are shown in FIG. 6, this is for comparison with the prior art of FIG. 2 (b) in which only one main seal is formed, When the first sealing line 200 is cut, the second sealing line 400 is finally left in the pouch case 100. That is, the second sealing line 400 of this embodiment can correspond to the main sealing of the prior art. However, while the prior art is such that the main seal is within the process chamber of the vacuum, in the case of the present embodiment the second seal is performed at atmospheric pressure outside the process chamber. Since the inside and outside of the pouch case 100 are adjusted in the same pressure, wrinkles are not generated even when the pouch case 100 is sealed for a second time, and wrinkles are prevented from being generated, Not only can it be prevented but also an effect of improving the insulation voltage can be obtained.

FIG. 7 (a) is an image of a pouch case manufactured by a conventional battery cell manufacturing method, and FIG. 7 (b) is an image of a pouch case manufactured by a method of manufacturing a battery cell according to an embodiment of the present invention.

Referring to FIG. 7 (a), in the case of the conventional method for manufacturing a battery cell 10, the process is terminated by one main sealing and cutting in a vacuum processing chamber, so that gas is removed from the inside of the processing chamber, At this time, the pouch case 100 is wrinkled due to a pressure difference between the inside of the vacuum processing chamber and the outside of the atmospheric processing chamber. The insulation resistance defect rate of the battery cell 10 thus manufactured is 44%.

Referring to FIG. 7 (b), a method of manufacturing a battery cell 10 according to an embodiment of the present invention includes forming a first sealing line 200 And the pressure inside the pouch case 100 is adjusted to be equal to the pressure inside the pouch case 100 through the cut space. After the pressure inside the pouch case 100 becomes equal to the pressure inside the pouch case 100, The wrinkles due to the pressure difference are not generated in the pouch case 100 because the second sealing line 400 is sealed. The insulation resistance defect rate of the battery cell 10 thus manufactured is 0%.

In the case of the conventional battery cell manufacturing method, quality is managed for each of a plurality of main sealing portions in the process chamber when the pouch case 2 has a plurality of pouches because all the pouches are sealed inside the process chamber. However, in the case of the battery cell manufacturing method according to the embodiment of the present invention, since the quality is managed along one line to the plurality of pouch cases 100 sealed outside the process chamber, the quality management positions are unified, There is an easy effect.

Meanwhile, the battery cell 10 according to an embodiment of the present invention can be manufactured by the above-described method of manufacturing the battery cell 10, and the battery module 10 can be manufactured by stacking a plurality of such battery cells 10, Can be produced.

Meanwhile, the battery module according to an embodiment of the present invention may include the battery cell 10 manufactured by the above-described method. Here, the battery module may include a cartridge assembly for housing the battery cell 10, and a housing in which the cartridge assembly is housed. A number of cartridge assemblies can be stacked and can be made from plastic injection molding. The battery module may be provided with a connector element (not shown) or a terminal element (not shown). The connector element (not shown) may include various types of electrical connection parts or connections (not shown) to be connected to a BMS (Battery Management System, not shown) capable of providing data on the voltage or temperature of the battery cell 10, Member may be included. The terminal element (not shown) includes a positive electrode terminal and a negative electrode terminal as main terminals connected to the battery cell 10, and a terminal element (not shown) may be electrically connected to the outside with a terminal bolt.

Meanwhile, a battery pack (not shown) according to an embodiment of the present invention may include at least one battery module including the battery cell 10 to the battery cell 10 manufactured by the above-described method. In addition to the battery module, the battery pack (not shown) may further include a case for accommodating the battery module and various devices for controlling charge / discharge of the battery module, such as a BMS, a current sensor, a fuse, .

A vehicle (not shown) according to an embodiment of the present invention may include the above-described battery cell 10, a battery module or a battery pack (not shown), and the battery pack May be included. The battery module according to an embodiment of the present invention may be applied to a vehicle (not shown), for example, an electric vehicle or a hybrid vehicle.

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 to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

10: battery cell 100: pouch case
200: first sealing line 300: cutting line
400: second sealing line 500: electrode assembly

Claims (8)

(a) transferring a pouch case activated by charge / discharge after packaging of an electrode assembly to a process chamber;
(b) discharging gas generated in the pouch case inside the process chamber;
(c) sealing the pouch case from which the gas is discharged, inside the process chamber;
(d) cutting the first sealed pouch case outside the process chamber; And
(e) the pouch case is secondly sealed outside the process chamber. The method according to claim 1,
Wherein the inside of the process chamber is in a vacuum state, and the outside of the process chamber is in an atmospheric pressure state. The method according to claim 1,
The step (b)
Wherein a gas discharge portion is formed in the pouch case inside the process chamber and gas is discharged from the pouch case inside the process chamber. The method according to claim 1,
The step (c)
Wherein a position of the first sealing is formed at a position spaced apart from the electrode assembly by a predetermined interval. The method according to claim 1,
The step (d)
Wherein a portion of the pouch case where the first sealing is formed is cut. The method according to claim 1,
The step (e)
Wherein the second sealing position is formed closer to the electrode assembly than the first sealing position with respect to the electrode assembly. A battery cell produced by the method for manufacturing a battery cell according to any one of claims 1 to 6. A battery module comprising a battery cell produced by the method for manufacturing a battery cell according to any one of claims 1 to 6.

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