Secondary Sealing Device for Pouch-Type Secondary Battery

Abstract

The present application relates to a secondary sealing device for a pouch-type secondary battery, and the secondary sealing device for a pouch-type secondary battery according to the present invention can perform gap correction between the electrode assembly and the secondary sealing line by aligning the position of the electrode assembly, thereby making it easy to manage the gap and providing products with uniform electrical characteristics.

Description

Technical Field

[0001] The present invention relates to a secondary sealing device for a pouch-type secondary battery, and more particularly, to a secondary sealing device for a pouch-type secondary battery applied to a secondary sealing process of a pouch-type secondary battery in which an electrolyte injection step, a primary sealing step, a charge / discharge step, and a degassing step are sequentially performed.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0010095 filed on January 24, 2022, and all contents disclosed in the corresponding Korean patent application are incorporated herein by reference.

Background Art

[0003] Secondary batteries capable of repeated charging and discharging can be classified into prismatic secondary batteries, cylindrical secondary batteries, pouch-type secondary batteries, etc. according to their manufacturing methods and structures. Among these, pouch-type secondary batteries are widely used because of their advantages of simple structure and large capacitance per unit volume.

[0004] Generally, a pouch-type secondary battery is manufactured by housing an electrode assembly in which an electrode tab is formed on one side of an electrode body including a negative electrode, a positive electrode, an electrolyte, and a separator (separation membrane) inside a pouch, injecting an electrolyte into the pouch, primary sealing the electrolyte injection part, charging, and performing a degassing process to remove gas, and then performing secondary sealing.

[0005] On the other hand, secondary sealing is performed by forming a secondary sealing line so as to form a gap with the electrode assembly inside the primary sealing line.

[0006] The gap is a factor that affects the electrical characteristics of the battery during the progress of subsequent processes, and management of the gap is required as essential to ensure that product specifications are constant.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention aims to solve the problem of providing a secondary sealing device for a pouch-type secondary battery that enables easy management of the gap between the secondary sealing line and the electrode assembly.

Means for Solving the Problem

[0008] To solve the above problems, according to one aspect of the present invention, there is provided a secondary sealing device for a pouch-type secondary battery including an electrode assembly and a pouch-type case, wherein a primary sealing line is formed at an electrolyte injection portion located at an edge of the pouch-type case, the secondary sealing device comprising: a transfer portion for transferring the pouch-type secondary battery; a sealing portion for forming a secondary sealing line so as to be positioned between the primary sealing line and the electrode assembly in a state of having a predetermined gap with the electrode assembly; and a gap correction portion provided to correct the gap in advance by aligning the position of the pouch-type secondary battery before the secondary sealing line is formed by the sealing portion.

[0009] Further, according to still another aspect of the present invention, there is provided a secondary sealing method for a pouch-type secondary battery, including the steps of: transferring a pouch-type secondary battery including an electrode assembly and a pouch-type case, in which a primary sealing line is formed at an electrolyte injection portion located at an edge of the pouch-type case, to a secondary sealing location; forming a secondary sealing line so as to have a gap with the electrode assembly inside the primary sealing line at the secondary sealing location; and aligning the position of the pouch-type secondary battery transferred to the secondary sealing location to correct the gap in advance.

Effect of the Invention

[0010] As confirmed above, according to the secondary sealing device for a pouch-type secondary battery according to the present invention, by aligning the position of the electrode assembly, it is possible to perform gap correction between the electrode assembly and the secondary sealing line. Accordingly, it is possible to easily manage the gap and provide products having the same specifications with identical electrical characteristics.

Brief Description of the Drawings

[0011]

Figure 1

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Figure 9

Modes for Carrying Out the Invention

[0012] Hereinafter, a secondary sealing device for a pouch-type secondary battery according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0013] Also, regardless of the reference numerals, the same or corresponding components are denoted by the same or similar reference numerals, and redundant descriptions thereof are omitted. For the sake of convenience of explanation, the sizes and shapes of the respective components illustrated may be exaggerated or reduced.

[0014] The present invention relates to a secondary sealing device for a pouch-type secondary battery including an electrode assembly and a pouch-type case, in which a primary sealing line is formed at an electrolyte injection portion located at an edge of the pouch-type case.

[0015] The secondary sealing device for a pouch-type secondary battery related to an embodiment of the present invention can be a device for secondarily sealing a pouch-type secondary battery that has sequentially performed an electrolyte injection process, a charge-discharge and degassing process.

[0016] The primary sealing line is formed in the primary sealing process, and the primary sealing process is performed after the electrolyte injection is completed.

[0017] FIG. 1 is a cross-sectional view showing the structure of a pouch-type secondary battery 10 in which a primary sealing line 13 is formed.

[0018] Referring to FIG. 1, the pouch-type secondary battery 10 that has completed the primary sealing process has a predetermined length l, height h, and thickness t. Also, the pouch-type secondary battery 10 includes an electrode assembly 11 in which an electrode tab 11b is formed on one side of an electrode body 11a including a negative electrode, a positive electrode, an electrolyte, and a separator (separation membrane), and a pouch-type case 12 surrounding the electrode assembly 11. At this time, the primary sealing line 13 is formed in the electrolyte injection part located at the edge of the pouch-type case 12.

[0019] The secondary sealing device for a pouch-type secondary battery 10 related to an embodiment of the present application includes the electrode assembly 11 and the pouch-type case 12, and is a secondary sealing device for a pouch-type secondary battery 10 in which a primary sealing line 13 is formed in the electrolyte injection part located at the edge of the pouch-type case 12.

[0020] In this document, the primary and secondary sealing lines mean joining lines for sealing the electrode assembly 11 inside the pouch-type case 12, and are formed at the edge of the pouch-type case 12 so as to surround the electrode assembly 11.

[0021] FIG. 2 is a cross-sectional view showing the structure of a pouch-type secondary battery in which a secondary sealing line is formed, and FIG. 3 is a drawing showing the configuration of an exemplary device according to the present invention.

[0022] The secondary sealing device for a pouch-type secondary battery related to an embodiment of the present invention includes a transfer unit 100 that transfers the pouch-type secondary battery, a secondary sealing line 220 located between the primary sealing line 13 and the electrode assembly 11, a sealing unit 200 that forms the secondary sealing line 220 such that the secondary sealing line 220 has a predetermined gap 210 from the electrode assembly 11, and a gap correction unit 300 provided to correct the gap 210 in advance by aligning the position of the pouch-type secondary battery 10 before the secondary sealing line 220 is formed by the sealing unit 200.

[0023] FIG. 4 is a drawing showing the operating state of an exemplary driving unit according to the present invention, FIG. 5 is a drawing for explaining the transfer direction of an exemplary transfer unit according to the present invention, FIGS. 6 to 8 are drawings for explaining exemplary gap corrections according to the present invention, and FIG. 9 is a drawing for explaining the operating state of an exemplary sealing unit according to the present invention.

[0024] The secondary sealing device for the pouch-type secondary battery includes a transfer unit 100, a sealing unit 200, and a gap correction unit 300.

[0025] The transfer unit 100 transfers the pouch-type secondary battery 10 to the location for secondary sealing. The transfer unit 100 serves to transfer the pouch-type secondary battery that has completed the degassing process to the location for secondary sealing. At this time, the location for secondary sealing means the location where the sealing unit 200 is provided.

[0026] The sealing unit 200 forms the secondary sealing line 220 at the location for secondary sealing such that it has a gap 210 from the electrode assembly 11 inside the primary sealing line 13. The sealing unit 200 forms the secondary sealing line 220 so as to be located between the primary sealing line 13 and the electrode assembly 11 in a state where it has a predetermined gap 210 from the electrode assembly 11. That is, the secondary sealing line 220 has a predetermined gap 210 from the electrode assembly 11 and is located between the primary sealing line 13 and the electrode assembly 11.

[0027] The secondary sealing line 220 can form a predetermined interval not only with the electrode assembly 11 but also with the primary sealing line 13. However, in the present invention, the term "gap 210" shall mean the gap between the secondary sealing line 220 and the electrode assembly 11. For example, the gap 210 has a constant interval between the secondary sealing line 220 and the electrode assembly 11, and the interval is the distance between the lower end of the secondary sealing line 220 and the upper end of the electrode assembly 11 with reference to FIG. 2, and can be defined based on the shortest distance between the secondary sealing line 220 and the electrode assembly 11.

[0028] The gap correction unit 300 aligns the position of the pouch-type secondary battery 10 transferred to the position of the secondary seal and performs correction of the gap 210 in advance.

[0029] In the present invention, gap correction means correcting the error between the gap of a standard product (a product having standard specifications) and the gap of the currently produced product. The gap of the standard product may vary for each model of the produced product. For example, when the gap of the standard product is 2 mm and the gap of the currently produced product is 2 mm or more or less, correcting the gap of the currently produced product to be 2 mm is called gap correction.

[0030] Such a gap 210 can be adjusted by adjusting the position of the secondary seal of the sealing part 200 or by adjusting the position of the pouch-type secondary battery 10 located within the sealing part 200.

[0031] In the present invention, the sealing part 200 is provided to perform secondary sealing at a preset same position (or fixed coordinates), and the gap 210 correction is performed by changing the position of the pouch-type secondary battery 10 before the formation of the secondary sealing line 220.

[0032] Referring to FIGS. 6 to 8, FIG. 6 shows an example in which the primary sealing line is formed asymmetrically, FIG. 7 shows an example in which the electrode assembly is formed asymmetrically, and FIG. 8 shows an example in which the primary sealing line and the electrode assembly are formed asymmetrically.

[0033] Referring to FIGS. 6(a), 7(a), and 8(a), due to tolerances of mechanical parts, dimensional errors of the electrode assembly, etc., the formation position of the primary sealing line 13 and the position of the electrode assembly may vary from product to product (meaning a pouch-type secondary battery). Such differences induce the occurrence of errors in the product gap during the secondary sealing line formation process.

[0034] Since the gap is a factor that affects the electrical characteristics of the battery, when an error in the gap occurs, there is a problem that the specifications between products change. Accordingly, the secondary sealing device according to the present invention can perform gap correction in advance before the secondary sealing is performed to minimize the gap error that may occur between products and provide products having the same specifications.

[0035] In one example, the gap correction unit 300 may include an image providing unit 310, an image inserting unit 320, an image analyzing unit 330, an arithmetic unit 340, and a driving unit 350.

[0036] The image providing unit 310 can provide a vertical cross-sectional image 311 of the space between the primary sealing line 13 and the electrode assembly 11 (see FIGS. 6(a), 7(a), and 8(a)). The vertical cross-sectional image is provided in a 2D form. The upper end of the vertical cross-sectional image 311 corresponds to the lower end of the primary sealing line 13, and the lower end of the vertical cross-sectional image 311 corresponds to the upper end of the electrode assembly 11.

[0037] The image insertion unit 320 can insert the virtual secondary sealing line 321 into the coordinates fixed to the vertical cross-sectional image 311 (see (b) of FIG. 6, (b) of FIG. 7, and (b) of FIG. 8). The virtual secondary sealing line 321 means a cross-sectional image of the secondary sealing line 220 actually formed in the sealing part 200, the coordinates are the coordinates with respect to the formation position of the secondary sealing line 220 actually formed in the sealing part 200, and the fixed coordinates can be the coordinates with respect to the formation position of the secondary sealing line 220 in the standard product.

[0038] That is, as described above, since the sealing part 200 is provided to perform the secondary sealing at the preset same position (or fixed coordinates), the image insertion unit 320 can insert the virtual secondary sealing line 321 into the coordinates fixed to the vertical cross-sectional image 311. At this time, the coordinates with respect to the formation position of the secondary sealing line 220 are coordinates that can be arbitrarily set by the user and can be set differently for each product model.

[0039] Referring to FIG. 3, (b) of FIG. 6, (b) of FIG. 7, and (b) of FIG. 8, the image analysis unit 330 can analyze the gap error in the vertical cross-sectional image 311 into which the virtual secondary sealing line 321 is inserted. The gap error is analyzed by comparing it with the gap arbitrarily set by the user (which can vary according to the required specifications of the product).

[0040] The calculation unit 340 can calculate the moving distance of the pouch-type secondary battery required for gap correction from the analyzed result. The calculation unit 340 can calculate the moving distance of the pouch-type secondary battery only by the gap error.

[0041] The driving unit 350 can move the pouch-type secondary battery based on the calculated moving distance. As the pouch-type secondary battery moves through the driving unit 350, gap correction can be performed between the virtual secondary sealing line 321 and the electrode assembly 11, and the inter-product gap can be formed to be constant. The secondary sealing device according to the present invention has the advantage of easy gap management through the above-described gap correction.

[0042] In one example, the calculation unit 340 can calculate the moving distances of both ends along the length direction (l, see FIG. 1) of the pouch-type secondary battery. For example, referring to FIGS. 6(b), 7(b), and 8(b), the calculation unit 340 uses the vertical cross-sectional image 311 to measure the distances from a to a' (hereinafter, JPEG0007703831000001.jpg3527) and from b to b' (hereinafter, JPEG0007703831000002.jpg3025), respectively, and can calculate the moving distances (X(a), X(b)) of the pouch-type secondary battery required for gap correction through a reference gap (hereinafter, Y) arbitrarily set by the user as shown in Equation 1 below. [Equation 1] [Number] The X(a) is the transfer distance of one end of the pouch-type secondary battery corresponding to the distance from a to a' in the vertical cross-sectional image 311, and the X(b) means the transfer distance of the other end of the pouch-type secondary battery corresponding to the distance from b to b' in the vertical cross-sectional image 311.

[0043] That is, when the driving unit 350 calculates the transfer distances required for gap correction through the calculation unit 340, it can transfer both ends of the pouch-type secondary battery along the height direction (h, see FIG. 1).

[0044] In one specific example, the drive unit 350 may include ball screws 351 disposed at both ends along the length direction of the pouch-type secondary battery and a servo motor 353 that drives the ball screws 351.

[0045] The image providing unit 310 may include a vision camera 315. The vision camera 315 can provide the vertical cross-sectional image 311 based on the contrast difference.

[0046] The transfer unit 100 may include a mounting portion on which the pouch-type secondary battery is vertically mounted so that the pouch-type secondary battery is transferred in the thickness direction t.

[0047] Referring to FIG. 5, the pouch-type secondary battery 10 is transferred in an upright state by the transfer unit 100. In the present application, the upright state means a state in which the pouch-type secondary battery is arranged along the height direction h on the mounting portion such that the electrode assembly 11 is located at the lower part and the primary sealing line 13 is located at the upper part.

[0048] When transferring the pouch-type secondary battery in the length direction l or the height direction h of the pouch-type secondary battery, there is a disadvantage in that the layout becomes long. In contrast, referring to FIG. 5, the transfer unit 100 has the effect of minimizing the layout by transferring the pouch-type secondary battery in the thickness direction t, which is shorter than the length l and the height h.

[0049] Referring to FIG. 9, the sealing portion 200 is a device that forms a bonding line by heating and pressing the edge of a pouch-type case surrounding the electrode assembly. The sealing portion 200 is disposed so as to face one surface of the pouch-type secondary battery 10, and includes a support portion 230 disposed so as to face one surface of the pouch-type secondary battery 10 and a sealing and pressing portion 240 that presses the other surface of the pouch-type secondary battery 10 while moving toward the support portion 230 side to form a secondary sealing line. The sealing and pressing portion 240 is provided to heat and press a region in contact with the pouch-type case. The support portion 230 may be provided to heat a region in contact with the pouch-type case.

[0050] Referring to FIG. 9, in the same manner as the method of being transported by the transport portion 100, the pouch-type secondary battery 10 is positioned in an upright state by the sealing portion 200, and the sealing and pressing portion 240 is provided to move toward the support portion 230 along the thickness direction t of the pouch-type secondary battery.

[0051] Further, the position of the support portion 230 is fixed and does not move, and only the sealing and pressing portion 240 is designed to move in a direction approaching or moving away from the support portion 230 along a certain moving path. Also at this time, the moving path of the sealing and pressing portion 240 is fixedly set so that the secondary sealing is made identical in the virtual fixed coordinates.

[0052] As described above, the pouch-type secondary battery 10 is in an upright state along the height direction h by the sealing portion 200. In such a state, the driving portion 350 moves both ends in the length direction (l, see FIG. 1) of the pouch-type secondary battery along the height direction (h, see FIG. 1) by a transport distance required for gap correction. As a result, gap correction between the electrode assembly and the secondary sealing line can be performed before the secondary sealing process is carried out.

[0053] Further, the present application relates to a method for secondary sealing of a pouch-type secondary battery. The method is carried out using the secondary sealing device for a pouch-type secondary battery described above. Therefore, descriptions overlapping with the above-described content will be omitted below.

[0054] Specifically, the secondary sealing method of the pouch-type secondary battery includes the steps of transferring a pouch-type secondary battery including the electrode assembly and the pouch-type case, in which a primary sealing line is formed at an electrolyte injection part located at an edge of the pouch-type case, to a secondary sealing location. Further, the secondary sealing method of the pouch-type secondary battery includes the step of forming a secondary sealing line so as to have a gap with the electrode assembly inside the primary sealing line at the secondary sealing location. Further, the secondary sealing method of the pouch-type secondary battery includes the step of aligning the position of the pouch-type secondary battery transferred to the secondary sealing location to correct the gap in advance.

[0055] In one example, the step of performing the gap correction in advance includes the steps of providing a vertical cross-sectional image of a space between the primary sealing line and the electrode assembly, inserting a virtual secondary sealing line at fixed coordinates into the vertical cross-sectional image, analyzing a gap error with the vertical cross-sectional image in which the virtual secondary sealing line is inserted, calculating a moving distance of the pouch-type secondary battery required for gap correction from the analyzed image, and moving the pouch-type secondary battery based on the calculated moving distance.

[0056] The calculating step can calculate the moving distances of both ends along the length direction of the pouch-type secondary battery.

[0057] And the transferring step can include the step of vertically mounting the pouch-type secondary battery so that the pouch-type secondary battery is transferred in the thickness direction.

[0058] The preferred embodiments of the present invention described above are disclosed for illustrative purposes, and those of ordinary skill in the art who have knowledge of the present invention can make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be understood to belong to the following claims.

Industrial Applicability

[0059] According to the secondary sealing device of the pouch-type secondary battery according to the present invention, by aligning the position of the electrode assembly, gap correction between the electrode assembly and the secondary sealing line can be performed. Along with this, gap management is easy, and products having the same specifications with the same electrical characteristics can be provided.

Claims

1. A secondary sealing device for a pouch-type secondary battery, comprising an electrode assembly body and a pouch-type case, wherein a primary sealing line is formed at an electrolyte injection portion located at an edge of the pouch-type case, the secondary sealing device comprising: a transfer portion for transferring the pouch-type secondary battery; a sealing portion for forming a secondary sealing line so as to be located between the primary sealing line and the electrode assembly body in a state of having a predetermined gap from the electrode assembly body; and a gap correction portion provided to correct the gap in advance by aligning the position of the pouch-type secondary battery before the secondary sealing line is formed by the sealing portion, wherein the gap correction portion an image providing portion for providing a vertical cross-sectional image of a space between the primary sealing line and the electrode assembly body; an image insertion portion for inserting a virtual secondary sealing line into fixed coordinates in the vertical cross-sectional image; an image analysis portion for analyzing a gap error in the vertical cross-sectional image into which the virtual secondary sealing line is inserted; a calculation portion for calculating a moving distance of the pouch-type secondary battery required for gap correction from the analyzed result; and a driving portion for moving the pouch-type secondary battery based on the calculated moving distance; including a secondary sealing device for a pouch-type secondary battery.

2. The secondary sealing device for a pouch-type secondary battery according to claim 1, wherein the calculation portion calculates moving distances of both end portions along the length direction of the pouch-type secondary battery.

3. The driving portion a ball screw disposed at both end portions along the length direction of the pouch-type secondary battery; and a servo motor for driving the ball screw, the secondary sealing device for a pouch-type secondary battery according to claim 2.

4. The secondary sealing device for a pouch-type secondary battery according to claim 1, wherein the image providing portion includes a vision camera.

5. A secondary sealing device for a pouch-type secondary battery, comprising an electrode assembly body and a pouch-type case, wherein a primary sealing line is formed at an electrolyte injection portion located at an edge of the pouch-type case, the secondary sealing device comprising: a transfer portion for transferring the pouch-type secondary battery; a sealing portion for forming a secondary sealing line so as to be located between the primary sealing line and the electrode assembly body in a state of having a predetermined gap from the electrode assembly body; and A gap correction unit is provided to correct the gap in advance by aligning the position of the pouch-type secondary battery before the secondary sealing line is formed by the sealing unit. The transfer unit includes a mounting unit on which the pouch-type secondary battery is vertically mounted so that the pouch-type secondary battery is transferred in the thickness direction, and is a secondary sealing device for the pouch-type secondary battery. **Claim 6**: A secondary sealing device for a pouch-type secondary battery including an electrode assembly and a pouch-type case, wherein a primary sealing line is formed at an electrolyte injection part located at an edge of the pouch-type case. A transfer unit for transferring the pouch-type secondary battery; A sealing unit for forming a secondary sealing line so as to be located between the primary sealing line and the electrode assembly in a state of having a predetermined gap from the electrode assembly; and A gap correction unit is provided to correct the gap in advance by aligning the position of the pouch-type secondary battery before the secondary sealing line is formed by the sealing unit. The sealing unit includes: A support unit arranged to face one surface of the pouch-type secondary battery; and A sealing pressure unit arranged to face one surface of the pouch-type secondary battery, moving to the support unit side, and pressing the other surface of the pouch-type secondary battery to form the secondary sealing line. It is a secondary sealing device for a pouch-type secondary battery. **Claim 7** The pouch-type secondary battery is positioned in an upright state at the sealing unit. The sealing pressure unit is provided to move to the support unit side along the thickness direction of the pouch-type secondary battery. The secondary sealing device for the pouch-type secondary battery according to claim 6. **Claim 8** A step of transferring a pouch-type secondary battery including an electrode assembly and a pouch-type case, in which a primary sealing line is formed at an electrolyte injection part located at an edge of the pouch-type case, to a secondary sealing location; A step of forming a secondary sealing line so as to have a gap from the electrode assembly inside the primary sealing line at the secondary sealing location; A step of aligning the position of the pouch-type secondary battery transferred to the secondary sealing location to correct the gap in advance, The step of correcting the gap in advance includes: A step of providing a vertical cross-sectional image of the space between the primary sealing line and the electrode assembly; Inserting into the virtual secondary sealing line in the vertical cross-sectional image at the fixed coordinates; Analyzing the gap error in the vertical cross-sectional image with the virtual secondary sealing line inserted; Calculating the moving distance of the pouch-type secondary battery required for gap correction from the analyzed image; and Moving the pouch-type secondary battery based on the calculated moving distance, A secondary sealing method for a pouch-type secondary battery.

9. The method for secondary sealing of a pouch-type secondary battery according to claim 8, wherein the calculating step calculates the moving distances of both ends along the length direction of the pouch-type secondary battery.

10. Transferring a pouch-type secondary battery including an electrode assembly and a pouch-type case, with a primary sealing line formed at an electrolyte injection part located at the edge of the pouch-type case, to a secondary sealing location; Forming a secondary sealing line at the secondary sealing location so as to have a gap with the electrode assembly inside the primary sealing line; Aligning the position of the pouch-type secondary battery transferred to the secondary sealing location and pre-correcting the gap, The transferring step includes A method for secondary sealing of a pouch-type secondary battery, including a step of vertically mounting the pouch-type secondary battery so that the pouch-type secondary battery is transferred in the thickness direction.

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