Pouch bag for secondary battery and pouch-type secondary battery including the same

Abstract

The present invention relates to an openable pouch bag and a pouch-type secondary battery including the same, and has an economical effect since no pouch bag is discarded after the degassing process.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0107274 filed on August 13, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a pouch bag for a secondary battery and a pouch-type secondary battery including the same. [Background technology]

[0003] Secondary batteries are widely used as power sources for mobile devices such as mobile phones, laptops, camcorders, etc. In particular, the use of lithium secondary batteries is rapidly increasing due to their advantages of high operating voltage and high energy density per unit weight.

[0004] Such lithium secondary batteries mainly use lithium-based oxides as positive electrode active materials and carbon materials as negative electrode active materials, and are generally classified into lithium ion batteries, lithium ion polymer batteries, and lithium polymer batteries depending on the type of electrolyte used, and into cylindrical, prismatic, and pouch-type secondary batteries depending on the battery shape. Prismatic and pouch-type secondary batteries are typically in high demand due to their thin thickness and being applicable to products such as mobile phones.

[0005] Among these, pouch-type secondary batteries have been attracting attention because they are not limited in shape or size, are easy to assemble through heat sealing, and are easily effective at discharging gas or liquid in the event of abnormal behavior, making them particularly suitable for manufacturing lightweight, thin cells. Generally, pouch-type secondary batteries have a structure in which an electrode assembly is housed in a pouch bag made of an aluminum laminate sheet. That is, pouch-type secondary batteries are manufactured by forming a receiving portion in the aluminum laminate sheet for mounting the electrode assembly, and then, with the electrode assembly mounted in the receiving portion, heat sealing a separate aluminum laminate sheet or an extended aluminum laminate sheet that is separated from the aluminum laminate sheet.

[0006] In a method for manufacturing a pouch-type secondary battery, an electrode assembly is placed in the housing, an electrolyte is injected, and the pouch bag is sealed. An additional degassing process is then performed to remove gases contained in the electrolyte. The pouch-type secondary battery is then manufactured by cutting away unnecessary aluminum laminate sheets. The aluminum laminate sheets must be made large to prevent gas generation, resulting in a large amount of sheet being discarded after the degassing process.

[0007] Therefore, there is a need for a pouch bag that can be manufactured so that no sheets are discarded after the degassing process, taking into consideration economic efficiency. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Publication No. 10-2013-0134242 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide an openable pouch bag that can be opened, removed gas, and then closed in a degassing process for removing gas during the manufacturing process of a pouch-type secondary battery. [Means for solving the problem]

[0010] In order to achieve the above purpose, The present invention includes an electrode assembly housing and a sealing portion, The pouch bag for a secondary battery is provided with an opening and closing part that can be repeatedly opened and closed at the sealing part.

[0011] In one embodiment of the present invention, the pouch bag for a secondary battery is formed of a pouch film including a metal layer and an inner resin layer formed on one surface of the metal layer, The opening and closing part includes a protrusion part provided on one of the inner resin layers of two pouch films that are sealed together, and a protrusion fixing part provided on the other inner resin layer.

[0012] In one embodiment of the present invention, the sealing portion is positioned in a ring shape around the electrode assembly receiving portion, The opening and closing portion is formed on the left or right sealing portion based on the axis on which the electrode terminal is positioned when the electrode assembly is housed.

[0013] In one embodiment of the present invention, the protrusion portion comprises a protrusion protruding from a surface of the inner resin layer, The protrusion fixing portion has a groove recessed from the surface of the inner resin layer.

[0014] In one embodiment of the present invention, the protrusions are formed in a plurality of numbers on a surface of the inner resin layer in a straight line, A large number of the recessed grooves are formed on the surface of the inner resin layer in a straight line.

[0015] In one embodiment of the present invention, the protrusions are protruded in the form of spheres or polygonal pillars, The grooves are indented in the form of a sphere or a polygonal pillar.

[0016] In one embodiment of the present invention, the protrusions are formed in a continuous linear pattern on a surface of the inner resin layer, The recessed grooves are formed in a continuous linear shape on the surface of the inner resin layer.

[0017] In one embodiment of the present invention, the opening and closing part can be opened and closed by fitting and releasing the protrusion part and the protrusion fixing part.

[0018] The present invention also provides the pouch bag for a secondary battery of the present invention; an electrode assembly housed in the pouch bag for the secondary battery; and and a pouch-type secondary battery including the electrolyte solution filled in the pouch bag for the secondary battery. [Effects of the Invention]

[0019] The pouch bag of the present invention is reclosable, and when manufacturing a pouch-type secondary battery, the pouch bag can be opened to remove gas and then closed. Therefore, there is no pouch bag to be discarded after the gas removal process, which is an advantage that it is very economical. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram schematically illustrating the shape of a pouch-type secondary battery before an excess portion is removed during a manufacturing process of the conventional pouch-type secondary battery. [Figure 2] 1 is a diagram illustrating a degassing process in a conventional manufacturing process of a pouch-type secondary battery. [Figure 3] 1 is a diagram illustrating a degassing process in a conventional manufacturing process of a pouch-type secondary battery. [Figure 4] 1 is a diagram illustrating a degassing process in a conventional manufacturing process of a pouch-type secondary battery. [Figure 5] 1 is a diagram illustrating a degassing process in a conventional manufacturing process of a pouch-type secondary battery. [Figure 6] 1 is a diagram illustrating a degassing process in a conventional manufacturing process of a pouch-type secondary battery. [Figure 7] 1 is a perspective view showing the pouch bag of the present invention in an open state. FIG. [Figure 8] 1 is a perspective view showing the pouch bag of the present invention in a closed state. FIG. [Figure 9] 1 is a view showing a state in which an opening / closing part of a pouch bag is opened according to an embodiment of the present invention; [Figure 10] 1 is a cross-sectional view showing a state in which the opening and closing part of a pouch bag is open, according to an embodiment of the present invention. [Figure 11] 1 is a cross-sectional view showing a state in which the opening and closing part of a pouch bag is closed, according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand how the present invention may be practiced. However, the present invention may be embodied in several different forms and should not be construed as limited to the embodiments set forth herein.

[0022] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0023] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, based on the principle that an inventor can appropriately define the concept of a term in order to best explain his or her invention.

[0024] DETAILED DESCRIPTION OF THE INVENTION The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0025] FIG. 1 is a schematic diagram showing the shape of a pouch-type secondary battery before excess portions are removed during a conventional manufacturing process of the pouch-type secondary battery, in which an electrode assembly is housed in an electrode assembly housing 110.

[0026] 2 to 6 are diagrams briefly illustrating a degassing process in the manufacturing process of a pouch-type secondary battery using a conventional pouch bag.

[0027] The degassing process in the manufacturing process of a conventional pouch-type secondary battery will be described below.

[0028] 2, the electrode assembly 11 is placed in the electrode assembly receiving portion 110 of the pouch bag 100, and the sealing portion 120 of the outer periphery surrounding the electrode assembly 11, excluding the excess portion 14, is heat-sealed to seal it. Since the excess portion 14 is not sealed, the electrolyte is injected through the excess portion 14.

[0029] Next, as shown in Figure 3, one end 15 of the excess portion 14 is heat-sealed, and charging and discharging are performed to activate the pouch-type secondary battery 10 (formation process). The formation process is performed to form a protective coating of electrolyte on the surface of the electrode (especially the negative electrode) to suppress electrolyte decomposition in the completed secondary battery. Gas is generated inside the battery during the formation process, and the generated gas and excess electrolyte are collected in the excess portion 14.

[0030] 4, a through hole 17 is formed in the excess portion 14, and a degassing process is performed to discharge gas through the through hole 17. After the degassing process, the outer circumferential surface between the cut portion 16 and the electrode assembly 11 is sealed based on the cut portion 16, and the excess portion 14 is removed by cutting along the cut portion 16, as shown in FIG.

[0031] The conventional pouch-type bag 100 requires an excess portion 14 in which gas is trapped, and after a degassing process to remove the gas trapped in the excess portion 14, the excess portion 14 is removed by cutting along a cutting portion 16. This results in the generation of pouch bags that are discarded, which is uneconomical.

[0032] The present invention aims to provide a pouch bag that can be used to manufacture pouch-type secondary batteries without throwing away any pouch bags.

[0033] Hereinafter, a pouch bag for a secondary battery according to one embodiment will be described with reference to FIGS.

[0034] Fig. 7 shows an open state of a pouch bag 100 for a secondary battery according to an embodiment of the present invention, and Fig. 8 shows a closed state of the pouch bag 100 for a secondary battery according to an embodiment of the present invention. Fig. 8 shows that an electrode assembly 10 is housed in the electrode assembly housing 110.

[0035] 7 and 8, a pouch bag 100 for a secondary battery according to one embodiment of the present invention includes an electrode assembly receiving portion 110 and a sealing portion 120, and the sealing portion 120 is provided with an opening / closing portion 130 that can be repeatedly opened and closed.

[0036] The sealing part 120 is positioned in a ring shape around the electrode assembly receiving part 110, and the opening / closing part 130 is formed on the left or right side of the sealing part based on the axis on which the electrode terminals are positioned when the electrode assembly is received. Specifically, the sealing part 120 is positioned in a square ring shape around the electrode assembly receiving part 110.

[0037] The pouch bag 100 for a secondary battery is composed of a pouch film 200 including a metal layer 210 and an inner resin layer 220 formed on one surface of the metal layer 210 .

[0038] In one embodiment of the present invention, the opening / closing portion 130 includes a protrusion portion 221 provided on one of the inner resin layers 220 of two pouch films 200 that are sealed together, and a protrusion fixing portion 222 provided on the other inner resin layer, as shown in Figures 9 to 11.

[0039] The protrusion portion 221 has a protrusion protruding from the surface of the inner resin layer 220 , and the protrusion fixing portion 222 has a groove recessed from the surface of the inner resin layer 220 .

[0040] 9, the protrusions are formed in a plurality of numbers in a straight line on the surface of the inner resin layer 220. The protrusions may have a distance between adjacent protrusions. The recessed grooves are formed in a plurality of numbers in a straight line on the surface of the inner resin layer 220. In this case, the protrusions and grooves may be formed in the same number and with the same distance between them.

[0041] The protrusions are spherical or polygonal pillar-shaped and protrude from the surface of the inner resin layer 220, and the grooves are spherical or polygonal pillar-shaped and recessed from the surface of the inner resin layer 220. In this case, the shape of the protrusions and the shape of the grooves are the same.

[0042] 10, the protrusions are formed as continuous lines on a straight line on the surface of the inner resin layer 220, and the recessed grooves are formed as continuous lines on a straight line on the surface of the inner resin layer 220. The longitudinal cross sections of the protrusions and grooves may have a circular, polygonal, or other shape.

[0043] According to one embodiment of the present invention, the pouch bag 100 for secondary batteries of the present invention is opened and closed by fitting and releasing the protrusion 221 and the protrusion fixing part 222 together.

[0044] 9 and 10 show a state in which the opening / closing part 130 of the pouch bag for secondary batteries 100 is open. That is, Fig. 9 and Fig. 10 show a state in which the engagement between the protrusion part 221 and the protrusion fixing part 222 is released, and the protrusion of the protrusion part 221 is not engaged in the recessed groove of the protrusion fixing part 222.

[0045] 11 shows a state in which the opening / closing part 130 of the pouch bag 100 for a secondary battery is closed. That is, Fig. 11 shows a state in which the protrusion 221 and the protrusion fixing part 222 are fitted and coupled. More specifically, the protrusion of the protrusion 221 is fitted into the recessed groove of the protrusion fixing part 222, so that the opening / closing part 130 of the pouch bag 100 can be closed.

[0046] According to one embodiment of the present invention, the pouch bag 100 of the present invention can be opened and closed by fitting and releasing the protrusion 221 and the protrusion fixing portion 222. Therefore, no excess portion that traps gas is required when manufacturing a pouch-type secondary battery. Therefore, a step of cutting off the cut portion to remove the excess portion is not required, and no excess portion is required to be removed. Therefore, a pouch-type secondary battery can be manufactured without a pouch-type bag that needs to be discarded, which is economical.

[0047] Specifically, a degassing process can be performed to discharge gas while the protrusions 221 and the protrusion fixing parts 222 are released, i.e., while the pouch-type bag 100 is open. After the degassing process, the protrusions 221 and the protrusion fixing parts 222 are fitted together, i.e., the pouch-type bag 100 is closed, and finally, a pouch-type secondary battery can be manufactured.

[0048] Therefore, the pouch-type bag 100 according to one embodiment of the present invention can be opened and closed by fitting and releasing the protrusion 221 and the protrusion fixing portion 222, and does not need to include a separate excess portion that is discarded after collecting gas, so no pouch-type bag is discarded, making it very economical.

[0049] In addition, a pouch-type secondary battery according to an embodiment of the present invention includes the pouch bag according to the embodiment of the present invention described above; an electrode assembly housed in the pouch bag; and an electrolyte solution filled in the pouch bag.

[0050] The electrode assemblies and electrolytes are well known in the art.

[0051] Those skilled in the art will understand that various modifications can be made without departing from the essential characteristics of the above description. Therefore, the disclosed method should be considered from an illustrative rather than a restrictive perspective. The scope of the present invention is defined by the claims, not the above description, and all differences within the scope of the claims should be interpreted as being within the scope of the present invention. [Explanation of symbols]

[0052] 10: Pouch-type secondary battery 11: Electrode assembly 12, 13: Electrode terminal 14: Excess part 15: Excess end 16: Cutting section 17:Through hole 100: Pouch-type bag 110: Electrode assembly storage section 120: Sealing part 130: Opening and closing section 200: Pouch film 210: Metal layer 220: Internal resin layer 221:Protrusion 222:Protrusion fixing part

Claims

1. an electrode assembly receiving portion and a sealing portion; The sealing part is provided with an opening and closing part that can be repeatedly opened and closed to discharge gas, The pouch film includes a metal layer and an inner resin layer formed on one surface of the metal layer. The opening and closing part comprises a protrusion part provided on one inner resin layer of two pouch films sealed together and a protrusion fixing part provided on the other inner resin layer, the protrusion portion has a protrusion protruding from a surface of the inner resin layer, the protrusion fixing portion has a groove extending from the surface of the inner resin layer, The protrusions are formed in a large number in a straight line on the surface of the inner resin layer, The recessed grooves are formed in a number of straight lines on the surface of the inner resin layer, The opening / closing part can be opened and closed by fitting and unfitting the protrusion part and the protrusion fixing part. A pouch bag for a secondary battery, characterized in that:

2. The sealing portion is positioned around the electrode assembly receiving portion in the form of a ring, 2. The pouch bag for a secondary battery according to claim 1, wherein the opening and closing part is formed on the left or right sealing part based on an axis on which the electrode terminal is positioned when the electrode assembly is housed.

3. The protrusions are protruded in the shape of a sphere or a polygonal pillar, 2. The pouch bag for a secondary battery according to claim 1, wherein the groove is indented in the shape of a sphere or a polygonal pillar.

4. The pouch bag for a secondary battery according to any one of claims 1 to 3; an electrode assembly housed in the pouch bag for the secondary battery; and a pouch-type secondary battery including an electrolyte filled in the pouch bag for the secondary battery.

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