KR102143627B1 - Pouch type secondary battery - Google Patents

Abstract

Various embodiments of the present invention relate to a pouch-type secondary battery, and the technical problem to be solved is to increase the adhesion area between the sealing part and the pouch exterior material to improve adhesion and reduce the width spread of the pouch exterior material. An object of the present invention is to provide a pouch-type secondary battery capable of reducing damage to the pouch casing by an end portion of the sealing portion by allowing the pouch to face an outer direction rather than an inner direction.
To this end, the present invention includes an electrode assembly having a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates; And a first outer portion receiving one side of the electrode assembly, a second outer portion receiving the other side of the electrode assembly, and a sealing portion formed by sealing the first and second outer portions in a region corresponding to the outside of the electrode assembly. It includes an exterior material, and the sealing part includes an inner folding part folded from the pouch exterior material and an outer folding part folded outward from the inner folding part, and an adhesive interposed between the inner folding part and the pouch exterior material. Disclosed is a pouch type secondary battery.

Description

Pouch type secondary battery

Various embodiments of the present invention relate to a pouch type secondary battery.

A secondary battery is a battery capable of charging and discharging unlike a primary battery that cannot be charged. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, tablet computers, notebook computers, digital cameras and camcorders, and large-capacity secondary batteries are used as power and power for motor driving such as hybrid vehicles and electric vehicles It is widely used as a storage battery.

Such a secondary battery may include an electrode assembly comprising a positive electrode and a negative electrode, a case accommodating the same, and an electrode terminal connected to the electrode assembly. Secondary batteries can be classified into a circular shape, a square shape, and a pouch type, depending on their shape. Among them, the pouch-type secondary battery may be formed of a pouch exterior material that is easily deformable in various shapes and has a small weight.

The above-described information disclosed in the technology that serves as the background of the present invention is only for improving an understanding of the background of the present invention, and thus may include information that does not constitute the prior art.

The problem to be solved according to various embodiments of the present invention is that by interposing an adhesive between the sealing part and the pouch exterior material, the sealing part is strongly adhered to the pouch exterior material, thereby reducing battery width dispersion, and the end of the sealing part is An object of the present invention is to provide a pouch-type secondary battery capable of preventing damage to a pouch exterior material due to an end portion of a sealing portion by folding in an outer direction instead of an inner direction.

A pouch-type secondary battery according to various embodiments of the present disclosure includes an electrode assembly having a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates; And a first exterior part accommodating one side of the electrode assembly, a second exterior part accommodating the other side of the electrode assembly, and a sealing part formed by sealing the first and second exterior parts in a region corresponding to the outside of the electrode assembly. Including a pouch case, the sealing part includes an inner folding part folded from the pouch case and an outer folding part folded outward from the inner folding part, and an adhesive interposed between the inner folding part and the pouch case Can include.

It may further include an insulating tape adhered to the end of the outer folding portion.

The heat melting temperature of the adhesive may be 100 ℃ to 200 ℃.

The adhesive may include a thermoplastic resin or a thermosetting resin.

The adhesive strength of the adhesive may be 200 mPa to 600 mPa.

The pouch case may include a long side portion facing the long side area of the electrode assembly and a short side portion facing the short side area of the electrode assembly, the inner folding portion facing the short side portion, and the adhesive is the inner folding portion And may be interposed between the short side portion.

The pouch exterior material may further include a curved portion connecting the long side portion and the short side portion, the inner folding portion faces the curved portion, and the adhesive may be interposed between the inner folding portion and the curved portion.

The height of the outer folding part may be smaller than the height of the inner folding part.

An insulating tape is attached to the inner folding part and the outer folding part, so that the insulating tape may cover an end of the outer folding part.

Various embodiments of the present invention prevent damage to the pouch case by the end of the sealing unit by folding the end of the sealing unit in the outer direction rather than the inner direction of the pouch case, and the adhesive area between the sealing unit and the pouch case By interposing the adhesive to increase this, the folded sealing part is strongly adhered to the pouch case, thereby reducing battery width distribution, and preventing the bonded folding part from being hardened in an open state before the heat-melted adhesive is firmly fixed. .

That is, in various embodiments of the present invention, an adhesive is interposed between the entire inner folding part of the folded sealing part and the short side part of the pouch case, thereby increasing the adhesion area between the folded sealing part and the pouch case. Let it improve. As the adhesion is improved, the overall width of the pouch case is always kept constant, so that the width distribution of a plurality of pouch-type secondary batteries is reduced.

In addition, various embodiments of the present invention are characterized in that the outer folding part of the folded sealing part is folded in an outward direction away from the pouch case, not in an inner direction toward the pouch case, so that damage to the pouch case by the end of the outer folding part (in particular, the inner side Damage phenomenon of the pouch exterior material corresponding to the folding part) is prevented.

In addition, according to various embodiments of the present invention, the end of the outer folding part of the sealing part is finished with an insulating tape, so that the metal layer is not exposed to the outside through the end of the outer folding part. Accordingly, it is possible to prevent an electric short phenomenon caused by the external set and the metal layer.

1A to 1C are an exploded perspective view, a plan view, and a partial perspective view illustrating a secondary battery according to various embodiments of the present disclosure.
2 is a side view illustrating a folding and bonding state of a sealing portion of a pouch-type secondary battery according to various embodiments of the present disclosure.
3 is a side view illustrating a folding, bonding, and taping state of a sealing portion of a pouch-type secondary battery according to various embodiments of the present disclosure.
4A to 4F are side views illustrating a method of folding, bonding, and taping a pouch-type secondary battery according to various embodiments of the present disclosure.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are provided to more fully describe the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, and the scope of the present invention is as follows. It is not limited to the Examples. Rather, these embodiments are provided to make the present disclosure more faithful and complete, and to completely convey the spirit of the present invention to those skilled in the art.

In addition, in the following drawings, the thickness or size of each layer is exaggerated for convenience and clarity of description, and the same reference numerals in the drawings refer to the same elements. As used herein, the term "and/or" includes any and all combinations of one or more of the corresponding listed items. In addition, in this specification, "connected" means not only when the A member and the B member are directly connected, but also when the C member is interposed between the A member and the B member to indirectly connect the A member and the B member. do.

The terminology used herein is used to describe a specific embodiment and is not intended to limit the present invention. As used herein, singular forms may include plural forms unless the context clearly indicates otherwise. Also, when used herein, "comprise, include" and/or "comprising, including" refer to the shapes, numbers, steps, actions, elements, elements and/or groups of these mentioned. It is to specify existence and not to exclude the presence or addition of one or more other shapes, numbers, actions, elements, elements and/or groups.

Although the terms first, second, etc. are used herein to describe various members, parts, regions, layers and/or parts, these members, parts, regions, layers and/or parts are defined by these terms. It is obvious that not. These terms are only used to distinguish one member, part, region, layer or portion from another region, layer or portion. Accordingly, the first member, component, region, layer, or part described below may refer to the second member, component, region, layer, or part without departing from the teachings of the present invention.

Space-related terms such as "beneath", "below", "lower", "above", and "upper" are associated with one element or feature shown in the drawing. It can be used for easy understanding of other elements or features. Terms related to such spaces are for easy understanding of the present invention according to various process states or use states of the present invention, and are not intended to limit the present invention. For example, if an element or feature in a figure is flipped over, the element or feature described as “bottom” or “below” becomes “top” or “above”. Thus, "bottom" is a concept encompassing "top" or "bottom".

1A to 1C, an exploded perspective view, a plan view, and a partial perspective view of a secondary battery according to various embodiments of the present disclosure are shown. Here, FIG. 1A is a secondary battery before the sealing portion is folded, and FIGS. 1B and 1C are secondary batteries after the sealing portion is folded.

1A to 1C, the secondary battery 100 according to various embodiments of the present invention is formed on the outside of the electrode assembly 110, the pouch case 120, and the pouch case 120 to form a pouch. It includes an adhesive 130 for bonding the sealing portions 121b and 122b (or folding portion) of the exterior material 120 to the side of the pouch exterior material 120. Here, the embodiment of the present invention may further include an insulating tape (not shown) for finishing ends of the sealing portions 121b and 122b.

The electrode assembly 110 may include a negative electrode plate 111, a positive electrode plate 112, and a separator 113 interposed between the negative electrode plate 111 and the positive electrode plate 112. The electrode assembly 110 may be in a form in which the negative electrode plate 111, the separator 113, and the positive electrode plate 112 are stacked or wound in a jelly roll shape.

The negative electrode plate 111 may include, for example, but is not limited to, a negative electrode active material layer coated on both surfaces of a negative conductive metal thin plate, for example, a negative electrode current collector made of copper or nickel foil or mesh. Here, the negative active material layer is, for example, but not limited to, a carbon-based material, Si, Sn, tin oxide, tin alloy composite, transition metal oxide, lithium metal nitrite, or metal oxide. In the negative electrode uncoated portion in which the negative electrode active material layer is not formed on the negative electrode current collector plate, for example, but not limited to, a substantially flat negative electrode tab 114 may be fixed (eg, welded). That is, one end of the negative electrode tab 114 is electrically connected to the negative electrode uncoated part, and the other end may protrude and extend to the outside. In addition, an insulating member 114a is attached to the negative electrode tab 114 to prevent the negative electrode tab 114 from being short-circuited with the pouch case 120.

The positive electrode plate 112 may include, for example, but not limited to, a positive electrode active material layer coated on both surfaces of a positive electrode current collector plate made of a thin metal plate having excellent conductivity, for example, aluminum foil or mesh. Here, the cathode active material layer is, for example, but not limited to, a chalcogenide compound may be used, and as an example, complex metal oxides such as LiCoO2, LiMn2O4, LiNiO2, and LiNiMnO2 may be used. The positive electrode tab 115 may be fixed (eg, welded) to the positive electrode uncoated portion in which the positive electrode active material layer is not formed on the positive electrode current collector, for example, but is not limited thereto. In addition, the insulating member 115a is attached to the positive electrode tab 115 to prevent the positive electrode tab 115 from being short-circuited with the pouch case 120.

The separator 113 is interposed between the negative electrode plate 111 and the positive electrode plate 112 to prevent an electrical short between the negative electrode plate 111 and the positive electrode plate 112. In practice, a pair of separators 113 is provided, and a negative electrode plate 111 is sandwiched between the pair of separators 113. In addition, the separator 113, for example, but not limited to, may be made of any one selected from the group consisting of polyethylene, polypropylene, and a porous copolymer of polyethylene and polypropylene. The separator 113 may be formed to be wider than the negative plate 111 and the positive plate 112 in order to prevent an electric short between the negative electrode plate 111 and the positive plate 112.

Meanwhile, the electrode assembly 110 includes a relatively wide first long side area 110a, a relatively wide second long side area 110b as an area opposite to the first long side area 110a, and first and second long side areas. It may include four short-side regions 110c connecting (110a, 110b).

The pouch case 120 accommodates the electrode assembly 110 and is formed by sealing the outer periphery of the electrode assembly 110. The pouch exterior material 120 may substantially include a first exterior part 121 and a second exterior part 122 having one end connected to the first exterior part 121. Moreover, the first outer portion 121 accommodates one side of the electrode assembly 110 (for example, a first long side region 110a of the electrode assembly 110 and a portion of the short side region 110c around the electrode assembly 110). The first recess 121a may be included, and the second outer portion 122 may be formed on the other side of the electrode assembly 110 (for example, the second long side region 110b of the electrode assembly 110 and the periphery thereof). It may include a second recess 122a accommodating a part of the short side region 110c of. Here, only one of the first and second recesses 121a and 122a may be formed.

In addition, the peripheries or peripheries of the first and second outer portions 121 and 122 corresponding to the outer periphery of the electrode assembly 110 are thermally fused to each other, so that the electrode assembly 110 is approximately inside the pouch or pocket-type pouch outer material 120. ) Is accepted. That is, the pouch exterior material 120 is formed by bending the pouch exterior material 120 in the form of an integrally formed square plate about the middle based on the length direction of one side to form the first exterior part 121 and the second exterior part 122. Is formed. Moreover, the first and second outer portions 121 and 122 have first and second recesses (or cavities) 121a having a predetermined depth in which the electrode assembly 110 can be accommodated through press or drawing processing. , 122a) may be formed, and sealing portions 121b and 122b for mutual sealing of the first and second outer portions 121 and 122 may be formed on the outer peripheries of the first and second recesses 121a and 122a. The sealing portions 121b and 122b may be formed all along one side and the remaining three sides in which the first and second outer portions 121 and 122 are in integral contact.

Meanwhile, the negative electrode tab 114 and the positive electrode tab 115 of the electrode assembly 110 are drawn out to the outside through a region in which the first and second outer portions 121 and 122 are fused. In this case, the insulating members 114a and 115b formed on the cathode tab 114 and the anode tab 115 are sealed together on the sealing portions 121b and 122b. That is, the insulating members 114a and 115b are formed at the portions where the negative electrode tab 114 and the positive electrode tab 115 and the sealing portions 121b and 122b contact each other, so that the negative electrode tab 114 and the positive electrode tab 115 (120) to prevent electrical short circuit.

The pouch case 120 may be formed in a multilayer or laminate structure including, for example, but not limited to, a first insulating layer 120a, a metal layer 120b, and a second insulating layer 120c. Of course, in addition, various adhesive layers or functional layers may be further added, but a description thereof will be omitted so as not to obscure the subject matter of the present invention.

The first insulating layer 120a is an inner surface of the pouch case 120 and is formed of a material having insulating properties and thermal adhesion properties. Further, the first insulating layer 120a is formed on one surface of the metal layer 120b and forms an inner surface of the pouch case 120 facing the electrode assembly 110. The first insulating layer 120a is not limited, but may be formed of a cast polypropylene film, a modified polypropylene, or an equivalent thereof that does not react with an electrolyte or the like. When the electrode assembly 110 is accommodated in the first and second recesses 121a and 122a of the first and second exterior parts 121 and 122 and the first and second exterior parts 121 and 122 are folded to each other, the first and second exterior parts ( The first insulating layers 120a of 121 and 122 are in contact with each other. Accordingly, when the sealing parts 121b and 122b are thermally fused, the first insulating layers 120a of the first and second exterior parts 121 and 122 are adhered to each other to seal the pouch exterior material 120.

The metal layer 120b is interposed between the first insulating layer 120a and the second insulating layer 120c, and prevents moisture and oxygen from entering from the outside, and if an electrolyte is filled inside the pouch case 120 In addition, it plays a role in preventing its outflow. In addition, the metal layer 120b serves to maintain the mechanical strength of the pouch case 120. In general, the metal layer 120b is not limited, but may be formed of aluminum, aluminum alloy, iron, or iron alloy.

The second insulating layer 120c is an outer surface of the pouch case 120 and serves to alleviate mechanical and chemical impacts with external electronic devices. In addition, the second insulating layer 120c is formed on the other surface of the metal layer 120b, and forms the outer surface of the pouch case 120. The second insulating layer 120c is not limited, but may be formed of nylon, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), or an equivalent thereof.

Here, the metal layer 120b described above may be exposed to the outside along the periphery of the pouch case 120, that is, through the first and second insulating layers 120a and 120c.

Meanwhile, of the secondary battery 100 according to various embodiments of the present disclosure, the second outer portion 122 of the pouch outer material 120 is a plurality of substantially flat short side portions extending in a direction away from the second outer portion 122, respectively. It may include a (122c) and a plurality of short side portions (122c) respectively connected to the substantially flat long side portion (122d). Moreover, the short side portion 122c and the long side portion 122d may be connected to each other through a curved portion 122e in a curved shape. Here, the short side portion 122c, the long side portion 122d, and the curved portion 122e formed on the second outer portion 122 have been described, but the short side portion 121c, the long side in the same form for the first outer portion 121 It is natural that the portion 121d and the curved portion 121e may be formed (see FIG. 2). Of course, in some cases, the short side, the long side, and the curved portion of the first outer portion 121 may be omitted. That is, the first outer part 121 may have an overall flat shape.

In addition, a plurality of short side portions 121c and 122c, long side portions 121d and 122d, and curved portions 121e and 122e substantially form first and second recesses 121a and 122a for accommodating the electrode assembly 110. Can be defined.

Subsequently, the sealing portions 121b and 122b may include an inner folding portion 123a folded from the pouch case 120 and an outer folding portion 123b folded outward from the inner folding portion 123a. That is, the inner folding part 123a is, for example, not limited, and is folded toward the short side part 122c provided in the second outer part 122 of the pouch case 120, and the outer folding part ( 123b) may be folded in an outward direction away from the short side portion 122c. In other words, the inner folding part 123a is folded in a direction substantially parallel to the short side part 122c provided in the second outer part 122 of the pouch case 120, and the outer folding part 123b is inside It may be folded in a direction substantially parallel to the inner folding part 123a in an outward direction from the folding part 123a. The folding shape of the inner folding part 123a and the outer folding part 123b will be described again below.

The adhesive 130 is interposed between the inner folding part 123a and the pouch exterior material 120 to prevent the inner folding part 123a from being unfolded by a restoring force. That is, the adhesive 130 is interposed between the inner folding portion 123a and the short side portion 122c of the pouch case 120, so that the inner folding portion 123a does not spread from the short side portion 122c. For example, the adhesive 130 may be heated to approximately 100° C. to 200° C., interposed between the inner folding portion 123a and the short side portion 122c in a molten state, and then thermally compressed and cooled to be cured. At this time, in order to facilitate adhesion, the pressing tool is pressed at about 100°C to 150°C for less than 10 seconds and then re-adhered at room temperature (for example, about 10°C to 30°C) within about 10 seconds. It can be cooled and fixed by pressing. Here, the thermal melting temperature of the adhesive 130 may be lower than the thermal melting temperature of the non-stretched polypropylene film forming the sealing portions 121b and 122b. Therefore, when the adhesive 130 is applied and compressed, the non-stretched polypropylene film forming the sealing portions 121b and 122b is not remelted.

Specifically, the adhesive 130 may include, for example, but not limited to, a thermoplastic resin or a thermosetting resin including an inorganic filler (eg, silica, alumina, boehmite, etc.).

In addition, the heat melting temperature (ie, heat curing temperature) of the adhesive 130 may be, for example, but not limited to, about 100°C to 200°C. However, the heat melting temperature of the adhesive 130 should be lower than the heat melting temperature of the non-stretched polypropylene film as described above. That is, if the heat melting temperature of the adhesive 130 is higher than the heat fusion temperature of the non-stretched polypropylene film, the sealing parts 121b and 122b are opened during the attaching process of the folding part through application and compression of the melted adhesive 130 Because it can be or can be transformed.

Further, the adhesive force of the adhesive 130 may be approximately 200 mPa to 600 mPa. If the adhesive force of the adhesive 130 is less than about 200 mPa, there is a problem in that the inner folding part 123a from the pouch case 120 may be unfolded again. However, when the adhesive force of the adhesive 130 is approximately 200 mPa to 600 mPa, the inner folding portion 123a from the pouch exterior material 120 is not unfolded again. However, if the adhesive force of the adhesive 130 is greater than approximately 600 mPa, there is a problem that the purchase cost of the adhesive 130 increases. Here, the adhesive force of the adhesive 130 refers to the force when the inner folding part 123a is pulled out from the short side part 122c of the pouch exterior material 120 at an angle of approximately 180° and starts to be separated from each other. .

In addition, the thickness of the adhesive 130 may be, for example, but not limited to, approximately 1 μm to 10 μm. When the thickness of the adhesive 130 is less than about 1 μm, the adhesive strength between the inner folding part 123a and the pouch case 120 may be reduced. When the thickness of the adhesive 130 exceeds approximately 10 μm, the thickness of the secondary battery 100 may be unnecessarily increased.

In this way, in various embodiments of the present invention, the adhesive 130 is further interposed between the folded sealing portions 121b and 122b and the short side portion 122c of the pouch exterior material 120, and thus the folded sealing portion 121b, 122b) and the short side portion 122c of the pouch case 120 are firmly adhered to each other. Accordingly, the sealing portions 121b and 122b folded from the pouch exterior material 120 are not unfolded to their original positions, thereby reducing the width distribution of the pouch exterior material 120. In addition, by double folding so that the ends of the sealing parts 121b and 122b face the outer direction rather than the inner direction of the pouch case 120, the pouch case 120 by the ends of the sealing parts 121b and 122b ) Can be prevented from being damaged.

That is, in various embodiments of the present invention, the adhesive 130 is further interposed between the entire inner folding part 123a of the sealing parts 121b and 122b and the pouch exterior material 120, thereby increasing the adhesion area and folding accordingly. The adhesion between the sealing parts 121b and 122b and the pouch exterior material 120 is improved. As the adhesion is improved, the entire width of the pouch case 120 is maintained constant, so that the width distribution for each pouch type secondary battery is reduced. In addition, in various embodiments of the present invention, the outer folding portion 123b of the sealing portions 121b and 122b is folded in an outer direction away from the pouch outer material 120 rather than an inner direction toward the pouch outer material 120. Damage to the pouch exterior material 120 by the end portion of the portion 123b is prevented. For example, damage to a partial area of the pouch case 120 corresponding to the inner folding part 123a by the end of the outer folding part 123b is prevented.

Referring to FIG. 2, a side view of a folding and bonding state of a sealing portion of a pouch-type secondary battery according to various embodiments of the present disclosure is shown.

As shown in FIG. 2, the pouch exterior material 120 includes a first exterior portion 121 that substantially covers the upper portion of the electrode assembly 110 and a second exterior portion 122 that substantially covers the lower portion of the electrode assembly 110. In addition, it may include sealing portions 121b and 122b formed by sealing the first and second outer portions 121 and 122 in a region corresponding to the outside of the electrode assembly 110.

Here, the sealing portions 121b and 122b include an inner folding portion 123a folded downward from the pouch case 120 and an outer folding portion 123b folded upward and outward from the inner folding portion 123a. Include. Here, the outer direction is not an area between the inner folding part 123a and the short side part 122c of the pouch case 120 (that is, the short side part 122c of the second outer part 122), but the short side part. It means the outer direction of the inner folding part 123a away from (122c).

Moreover, the adhesive 130 between the inner folding portion 123a of the sealing portions 121b and 122b and the short side portion 122c of the pouch case 120 (that is, the short side portion 122c of the second outer portion 122). ) Is more interposed. Here, when the inner folding portion 123a of the sealing portions 121b and 122b extends to the curved portion 122e of the pouch case 120 (that is, the curved portion 122e of the second outer portion 122), The adhesive 130 may also be filled up to between the inner folding part 123a and the curved part 122e of the pouch case 120.

In this way, the inner folding part 123a of the sealing parts 121b and 122b is strongly/hardly adhered to the short side part 122c of the pouch case 120 with the adhesive 130, so that the sealing parts 121b and 122b The inner folding part (123a) of the pouch is not unfolded to the outside of the exterior material (120). Therefore, the spread of width for a plurality of secondary batteries is reduced. Moreover, by forming the adhesive layer 130 on the entire inner surface of the inner folding portion 123a facing the short side portion 122c of the pouch case 120, the short side portion 122c and the inner folding portion ( The adhesion between 123a) is improved, so that the inner folding part 123a is not separated from the short side part 122c of the pouch case 120.

In addition, the outer folding part 123b of the sealing parts 121b and 122b is not between the inner folding part 123a and the short side part 122c, but is folded outside of the inner folding part 123a, so that the outer folding part 123b It is possible to prevent damage to the pouch exterior material 120 caused by the end of ). That is, when the outer folding part 123b is folded inward, which is between the inner folding part 123a and the short side part 122c, the end of the outer folding part 123b due to external vibration or shock is the pouch exterior material 120 Although there is a case of tearing, the embodiment of the present invention allows the outer folding part 123b to face the outside rather than the inside, so that the above-described problem can be fundamentally prevented.

Referring to FIG. 3, a side view of a folding, bonding, and taping state of a sealing portion of a pouch-type secondary battery according to various embodiments of the present disclosure is shown.

As shown in FIG. 3, an insulating tape 140 may be further adhered to an end of the outer folding part 123b. That is, a series of insulating tapes 140 are further adhered to the inner folding part 123a and the outer folding part 123b, so that the insulating tape 140 covers the end of the outer folding part 123b. Here, the end of the outer folding part 123b means an upper end in the drawing.

As described above, the metal layer may be exposed to the outside through the end of the outer folding part 123b. However, as described above, since the insulating tape 140 is further adhered to the end of the outer folding part 123b, such a metal layer is not exposed to the outside, and thus unnecessary electrical connection between the metal layer and an external device (eg, set) Contact is blocked. Moreover, the outer folding part 123b and the inner folding part 123a are covered with an insulating tape 140, so that the outer folding part 123b is not spread outward and remains in close contact with the inner folding part 123a. Is done. Accordingly, the spread of width for a plurality of secondary batteries is further reduced.

In addition, the height (or length in the vertical direction) of the outer folding part 123b is preferably formed to be smaller than the height (or length in the vertical direction) of the inner folding part 123a. That is, if the height of the outer folding part 123b is equal to or greater than the height of the inner folding part 123a, process management is difficult and there is a risk that the end of the outer folding part 123b penetrates through the insulating tape 140.

Here, the insulating tape 140 substantially covers all of the short side portion 121c and the curved portion 121e of the first outer portion 121 and the curved portion 122e of the second outer portion 122, so that the inner side The folding part 123a and the outer folding part 123b may not be spread outward.

4A to 4F, side views of a method of folding, bonding, and taping a pouch-type secondary battery according to various embodiments of the present disclosure are shown.

4A, after accommodating an electrode assembly (not shown) inside the pouch case 120, that is, inside the first and second outer portions 121, 122, the pouch case corresponding to the outside of the electrode assembly ( When the circumference of the pouch 120 is sealed, sealing portions 121b and 122b having a substantially horizontal shape are formed along the circumference of the pouch case 120. That is, sealing portions 121b and 122b extending in an outer horizontal direction along the periphery of the pouch exterior material 120 are formed.

Subsequently, as shown in FIG. 4B, one side of the sealing portions 121b and 122b is folded in an upper direction and an inner direction to form an outer folding portion 123b. The length of the outer folding part 123b is formed to be shorter than the length of the remaining sealing parts 121b and 122b, so that the length of the outer folding part 123b is less than the length of the inner folding part 123a.

Subsequently, as shown in FIG. 4C, the other side of the sealing parts 121b and 122b is folded downward to form an inner folding part 123a. That is, by folding the sealing portions 121b and 122b extending from the pouch case 120 in the downward direction, the short side portion 122c of the pouch case 120 (that is, the short side portion 122c of the second outer portion 122) )) to form an inner folding part 123a in close contact or close to it.

Subsequently, as shown in FIG. 4D, an adhesive 130 is injected between the inner folding part 123a of the sealing parts 121b and 122b and the short side part 122c of the pouch case 120.

Here, the viscosity of the adhesive 130 may be approximately 5,000 mPa·s to 10,000 mPa·s so that the adhesive 130 can be easily injected between the inner folding part 123a and the short side part 122c.

If the viscosity of the adhesive 130 is lower than about 5,000 mPa·s, the adhesive 130 easily flows to other areas during the filling process of the adhesive 130, causing contamination problems, and the viscosity of the adhesive 130 is approximately 10,000. If it is higher than mPa·s, it takes a long time to fill the adhesive 130 between the inner folding portion 123a and the short side portion 122c, or the adhesive 130 is not filled.

Further, in order to liquefy the solid adhesive and maintain the viscosity, the adhesive container and feed syringe may be heated to approximately 100°C to 200°C. That is, when the temperature of the adhesive container and the supply syringe is lower than about 100°C, the solid adhesive does not sufficiently change into a liquid adhesive, and the viscosity is higher than approximately 10,000 mPa·s, so that the adhesive is folded inside using the supplied syringe. It is difficult to inject into the gap between the part and the pouch case. In addition, when the temperature of the adhesive container and the supply syringe is higher than about 200°C, the viscosity of the adhesive is higher than about 5,000 mPa·s, so that the adhesive injected into the gap between the inner folding part and the pouch case can easily flow to other areas. Contamination problems may arise.

Subsequently, when the filling of the melted adhesive 130 between the inner folding part 123a and the short side part 122c is completed, the inner folding part 123a and the outer folding using a thermocompression pressing tool before the adhesive hardens. The portion 123b is pressed toward the short side portion 122c. The adhesive is supplied by being melted at a temperature of approximately 100° C. to 200° C., and may exist in a solid state at room temperature. At this time, the thermocompression pressing tool presses the inner folding part 123a and the outer folding part 123b toward the short side part 122c of the pouch case within about 10 seconds at about 100°C to 150°C in order to facilitate adhesion.

If the temperature of the thermocompression pressing tool is lower than about 100°C, the adhesive 130 may be completely cured before the inner folding part and the short side part are attached to be fixed in an open state, and the temperature of the thermocompression tool is less than about 150°C If it is high, the curing operation of the adhesive may not be performed or the non-stretched polypropylene film forming the sealing portions 121b and 122b may be remelted. When the non-stretched polypropylene film is remelted, the sealing portion may be opened, weakened, or deformed.

Subsequently, as shown in FIG. 4E, when the pressing by the hot pressing pressing tool is completed, the cooling pressing tool is operated to cure and cool the adhesive 130. As an example, in order to facilitate curing and cooling of the adhesive, the cooling and pressing tool includes the inner folding part 123a and the outer folding part 123b within about 10 seconds at a room temperature of about 10° C. to 30° C. Press it toward 122c).

Here, the thermocompression pressurization tool and the cooling pressurization tool may be the same tool capable of adjusting a temperature range, or may be tools provided separately from each other.

As a result, the adhesive 130 is cured by such a thermocompression process, so that the inner folding portion 123a is firmly bonded to the short side portion 122c. That is, the inner folding portion 123a does not extend outward from the short side portion 122c.

Finally, as shown in FIG. 4F, an insulating tape 140 is further attached between the outer folding part 123b and the inner folding part 123a. That is, the outer folding part 123b and the inner folding part 123a including the end of the outer folding part 123b are finished with insulating tape 140 so that the end of the outer folding part 123b is not exposed to the outside. do. By the insulating tape 140, the outer folding part 123b is not unfolded in the horizontal direction, and the metal layer is not exposed to the outside through the end of the outer folding part 123b, so that there is an electrical short between the metal layer and the external device. The phenomenon is also prevented.

What has been described above is only one embodiment for implementing the pouch-type secondary battery according to the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the claims below, the gist of the present invention Without departing from, anyone of ordinary skill in the field to which the present invention pertains will have the technical spirit of the present invention to the extent that various changes can be implemented.

100; Secondary battery according to an embodiment of the present invention
110; Electrode assembly 120; Pouch exterior material
121; First outer part 121a; First recess
121b; Sealing part 121c; Short side
121d; Long side 121e; Curved part
122; Second outer part 122a; 2nd recess
122b; Sealing part 122c; Short side
122d; Long side 122e; Curved part
123a; Inner folding part 123b; Outer folding part
130; Glue 140; Insulating tape

Claims (10)

An electrode assembly having a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates; And
A first exterior part accommodating one side of the electrode assembly, a second exterior part accommodating the other side of the electrode assembly, and a sealing part formed by sealing the first and second exterior parts in a region corresponding to the outside of the electrode assembly, Including a pouch case having a long side portion facing the long side region of the electrode assembly and a short side portion facing the short side region of the electrode assembly,
The sealing portion includes an inner folding portion folded toward the short side portion provided in the second outer portion of the pouch case and an outer folding portion folded in an outward direction from the inner folding portion, but folded in an outward direction away from the short side portion, and , A pouch type secondary battery comprising an adhesive interposed between the inner folding part and the pouch case. The method of claim 1,
A pouch-type secondary battery, further comprising an insulating tape adhered to an end of the outer folding part. The method of claim 1,
The pouch type secondary battery, wherein the heat melting temperature of the adhesive is lower than the heat melting temperature of the sealing part. The method of claim 1,
The heat melting temperature of the adhesive is a pouch-type secondary battery, characterized in that the 100 ℃ to 200 ℃. The method of claim 1,
The adhesive is a pouch type secondary battery, characterized in that it contains a thermoplastic resin or a thermosetting resin. The method of claim 1,
A pouch-type secondary battery, characterized in that the adhesive strength of the adhesive is 200 mPa to 600 mPa. The method of claim 1,
The inner folding portion faces the short side portion, and the adhesive is interposed between the inner folding portion and the short side portion. The method of claim 7,
The pouch exterior material further includes a curved portion connecting the long side portion and the short side portion,
The inner folding part faces the curved part, and the adhesive is interposed between the inner folding part and the curved part. The method of claim 1,
The height of the outer folding part is smaller than the height of the inner folding part. The method of claim 1,
An insulating tape is attached to the inner folding part and the outer folding part, so that the insulating tape covers an end of the outer folding part.

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